diff --git a/paddlespeech/t2s/frontend/mix_frontend.py b/paddlespeech/t2s/frontend/mix_frontend.py
index 343747f8..628984cb 100644
--- a/paddlespeech/t2s/frontend/mix_frontend.py
+++ b/paddlespeech/t2s/frontend/mix_frontend.py
@@ -18,9 +18,9 @@ from typing import List
 import numpy as np
 import paddle
 
-from paddlespeech.t2s.frontend.en_frontend import EnFrontend
+from paddlespeech.t2s.frontend.en_frontend import English as EnFrontend
 from paddlespeech.t2s.frontend.ssml.xml_processor import MixTextProcessor
-from paddlespeech.t2s.frontend.zh_frontend import ZhFrontend
+from paddlespeech.t2s.frontend.zh_frontend import Frontend as ZhFrontend
 
 
 class MixFrontend():
@@ -28,7 +28,6 @@ class MixFrontend():
                  g2p_model="pypinyin",
                  phone_vocab_path=None,
                  tone_vocab_path=None):
-
         self.zh_frontend = ZhFrontend(
             phone_vocab_path=phone_vocab_path, tone_vocab_path=tone_vocab_path)
         self.en_frontend = EnFrontend(phone_vocab_path=phone_vocab_path)
@@ -55,15 +54,12 @@ class MixFrontend():
         else:
             return False
 
-    def get_segment(self, text: str) -> List[str]:
+    def split_by_lang(self, text: str) -> List[str]:
         # sentence --> [ch_part, en_part, ch_part, ...]
         segments = []
         types = []
-        flag = 0
-        temp_seg = ""
-        temp_lang = ""
 
-        # Determine the type of each character. type: blank, chinese, alphabet, number, unk and point.
+        # Determine the type of each character. type: chinese, alphabet, other.
         for ch in text:
             if self.is_chinese(ch):
                 types.append("zh")
@@ -74,31 +70,31 @@ class MixFrontend():
 
         assert len(types) == len(text)
 
-        for i in range(len(types)):
+        flag = 0
+        temp_seg = ""
+        temp_lang = ""
+
+        for i in range(len(text)):
             # find the first char of the seg
             if flag == 0:
                 temp_seg += text[i]
                 temp_lang = types[i]
                 flag = 1
-
             else:
                 if temp_lang == "other":
-                    if types[i] == temp_lang:
-                        temp_seg += text[i]
-                    else:
-                        temp_seg += text[i]
+                    # text start is not lang.
+                    temp_seg += text[i]
+                    if types[i] != temp_lang:
                         temp_lang = types[i]
-
                 else:
-                    if types[i] == temp_lang:
-                        temp_seg += text[i]
-                    elif types[i] == "other":
+                    if types[i] == temp_lang or types[i] == "other":
+                        # merge same lang or other
                         temp_seg += text[i]
                     else:
+                        # change lang
                         segments.append((temp_seg, temp_lang))
                         temp_seg = text[i]
-                        temp_lang = types[i]
-                        flag = 1
+                        temp_lang = types[i]  # new lang
 
         segments.append((temp_seg, temp_lang))
 
@@ -120,7 +116,7 @@ class MixFrontend():
             if instr.lower().startswith("<say-as"):
                 tmpSegments.append((instr, "zh"))
             else:
-                tmpSegments.extend(self.get_segment(instr))
+                tmpSegments.extend(self.split_by_lang(instr))
         ''' 2. 把zh的merge到一起，避免合成结果中间停顿
         '''
         segments = []
diff --git a/tests/unit/tts/test_mixfrontend.py b/tests/unit/tts/test_mixfrontend.py
new file mode 100644
index 00000000..fdfebf46
--- /dev/null
+++ b/tests/unit/tts/test_mixfrontend.py
@@ -0,0 +1,431 @@
+import re
+import tempfile
+
+from paddlespeech.t2s.frontend.mix_frontend import MixFrontend
+
+# mix zh & en phonemes
+phone_id_str = """
+<pad> 0
+<unk> 1
+AA0 2
+AA1 3
+AA2 4
+AE0 5
+AE1 6
+AE2 7
+AH0 8
+AH1 9
+AH2 10
+AO0 11
+AO1 12
+AO2 13
+AW0 14
+AW1 15
+AW2 16
+AY0 17
+AY1 18
+AY2 19
+B 20
+CH 21
+D 22
+DH 23
+EH0 24
+EH1 25
+EH2 26
+ER0 27
+ER1 28
+ER2 29
+EY0 30
+EY1 31
+EY2 32
+F 33
+G 34
+HH 35
+IH0 36
+IH1 37
+IH2 38
+IY0 39
+IY1 40
+IY2 41
+JH 42
+K 43
+L 44
+M 45
+N 46
+NG 47
+OW0 48
+OW1 49
+OW2 50
+OY0 51
+OY1 52
+OY2 53
+P 54
+R 55
+S 56
+SH 57
+T 58
+TH 59
+UH0 60
+UH1 61
+UH2 62
+UW0 63
+UW1 64
+UW2 65
+V 66
+W 67
+Y 68
+Z 69
+ZH 70
+a1 71
+a2 72
+a3 73
+a4 74
+a5 75
+ai1 76
+ai2 77
+ai3 78
+ai4 79
+ai5 80
+air2 81
+air3 82
+air4 83
+an1 84
+an2 85
+an3 86
+an4 87
+an5 88
+ang1 89
+ang2 90
+ang3 91
+ang4 92
+ang5 93
+angr2 94
+angr4 95
+anr1 96
+anr3 97
+anr4 98
+ao1 99
+ao2 100
+ao3 101
+ao4 102
+ao5 103
+aor1 104
+aor3 105
+aor4 106
+aor5 107
+ar2 108
+ar3 109
+ar4 110
+ar5 111
+b 112
+c 113
+ch 114
+d 115
+e1 116
+e2 117
+e3 118
+e4 119
+e5 120
+ei1 121
+ei2 122
+ei3 123
+ei4 124
+ei5 125
+eir4 126
+en1 127
+en2 128
+en3 129
+en4 130
+en5 131
+eng1 132
+eng2 133
+eng3 134
+eng4 135
+eng5 136
+engr4 137
+enr1 138
+enr2 139
+enr3 140
+enr4 141
+enr5 142
+er1 143
+er2 144
+er3 145
+er4 146
+er5 147
+f 148
+g 149
+h 150
+i1 151
+i2 152
+i3 153
+i4 154
+i5 155
+ia1 156
+ia2 157
+ia3 158
+ia4 159
+ia5 160
+ian1 161
+ian2 162
+ian3 163
+ian4 164
+ian5 165
+iang1 166
+iang2 167
+iang3 168
+iang4 169
+iang5 170
+iangr4 171
+ianr1 172
+ianr2 173
+ianr3 174
+ianr4 175
+ianr5 176
+iao1 177
+iao2 178
+iao3 179
+iao4 180
+iao5 181
+iaor1 182
+iaor2 183
+iaor3 184
+iaor4 185
+iar1 186
+iar3 187
+iar4 188
+ie1 189
+ie2 190
+ie3 191
+ie4 192
+ie5 193
+ii1 194
+ii2 195
+ii3 196
+ii4 197
+ii5 198
+iii1 199
+iii2 200
+iii3 201
+iii4 202
+iii5 203
+iiir1 204
+iiir4 205
+iir2 206
+in1 207
+in2 208
+in3 209
+in4 210
+in5 211
+ing1 212
+ing2 213
+ing3 214
+ing4 215
+ing5 216
+ingr1 217
+ingr2 218
+ingr3 219
+ingr4 220
+inr1 221
+inr4 222
+io1 223
+io3 224
+io5 225
+iong1 226
+iong2 227
+iong3 228
+iong4 229
+iong5 230
+iou1 231
+iou2 232
+iou3 233
+iou4 234
+iou5 235
+iour1 236
+iour2 237
+iour3 238
+iour4 239
+ir1 240
+ir2 241
+ir3 242
+ir4 243
+ir5 244
+j 245
+k 246
+l 247
+m 248
+n 249
+o1 250
+o2 251
+o3 252
+o4 253
+o5 254
+ong1 255
+ong2 256
+ong3 257
+ong4 258
+ong5 259
+ongr4 260
+or2 261
+ou1 262
+ou2 263
+ou3 264
+ou4 265
+ou5 266
+our2 267
+our3 268
+our4 269
+our5 270
+p 271
+q 272
+r 273
+s 274
+sh 275
+sil 276
+sp 277
+spl 278
+spn 279
+t 280
+u1 281
+u2 282
+u3 283
+u4 284
+u5 285
+ua1 286
+ua2 287
+ua3 288
+ua4 289
+ua5 290
+uai1 291
+uai2 292
+uai3 293
+uai4 294
+uai5 295
+uair4 296
+uan1 297
+uan2 298
+uan3 299
+uan4 300
+uan5 301
+uang1 302
+uang2 303
+uang3 304
+uang4 305
+uang5 306
+uangr4 307
+uanr1 308
+uanr2 309
+uanr3 310
+uanr4 311
+uanr5 312
+uar1 313
+uar2 314
+uar4 315
+uei1 316
+uei2 317
+uei3 318
+uei4 319
+uei5 320
+ueir1 321
+ueir2 322
+ueir3 323
+ueir4 324
+uen1 325
+uen2 326
+uen3 327
+uen4 328
+uen5 329
+ueng1 330
+ueng2 331
+ueng3 332
+ueng4 333
+uenr1 334
+uenr2 335
+uenr3 336
+uenr4 337
+uo1 338
+uo2 339
+uo3 340
+uo4 341
+uo5 342
+uor1 343
+uor2 344
+uor3 345
+uor5 346
+ur1 347
+ur2 348
+ur3 349
+ur4 350
+ur5 351
+v1 352
+v2 353
+v3 354
+v4 355
+v5 356
+van1 357
+van2 358
+van3 359
+van4 360
+van5 361
+vanr1 362
+vanr2 363
+vanr3 364
+vanr4 365
+ve1 366
+ve2 367
+ve3 368
+ve4 369
+ve5 370
+ver3 371
+ver4 372
+vn1 373
+vn2 374
+vn3 375
+vn4 376
+vn5 377
+vnr2 378
+vr3 379
+x 380
+z 381
+zh 382
+, 383
+. 384
+? 385
+! 386
+<eos> 387
+"""
+
+if __name__ == '__main__':
+    with tempfile.NamedTemporaryFile(mode='wt') as f:
+        phone_ids = phone_id_str.split()
+        for phone, id in zip(phone_ids[::2], phone_ids[1::2]):
+            f.write(f"{phone} {id}")
+            f.write('\n')
+            f.flush()
+
+        frontend = MixFrontend(phone_vocab_path=f.name)
+
+        text = "hello, 我爱北京天安们，what about you."
+        print(text)
+        # [('hello, ', 'en'), ('我爱北京天安们，', 'zh'), ('what about you.', 'en')]
+        segs = frontend.split_by_lang(text)
+        print(segs)
+
+        text = "hello?!!我爱北京天安们，what about you."
+        print(text)
+        # [('hello?!!', 'en'), ('我爱北京天安们，', 'zh'), ('what about you.', 'en')]
+        segs = frontend.split_by_lang(text)
+        print(segs)
+
+        text = "<speak> hello，我爱北京天安们，what about you."
+        print(text)
+        # [('<speak> hello，', 'en'), ('我爱北京天安们，', 'zh'), ('what about you.', 'en')]
+        segs = frontend.split_by_lang(text)
+        print(segs)
+
+        # 对于SSML的xml标记处理不好。
+        text = "<speak>我们的声学模型使用了 Fast Speech Two。前浪<say-as pinyin='dao3'>倒</say-as>在沙滩上,沙滩上倒了一堆<say-as pinyin='tu3'>土</say-as>。 想象<say-as pinyin='gan1 gan1'>干干</say-as>的树干<say-as pinyin='dao3'>倒</say-as>了, 里面有个干尸，不知是被谁<say-as pinyin='gan4'>干</say-as>死的。</speak>"
+        print(text)
+        # [('<speak>', 'en'), ('我们的声学模型使用了 ', 'zh'), ('Fast Speech Two。', 'en'), ('前浪<', 'zh'), ("say-as pinyin='dao3'>", 'en'), ('倒</', 'zh'), ('say-as>', 'en'), ('在沙滩上,沙滩上倒了一堆<', 'zh'), ("say-as pinyin='tu3'>", 'en'), ('土</', 'zh'), ('say-as>。 ', 'en'), ('想象<', 'zh'), ("say-as pinyin='gan1 gan1'>", 'en'), ('干干</', 'zh'), ('say-as>', 'en'), ('的树干<', 'zh'), ("say-as pinyin='dao3'>", 'en'), ('倒</', 'zh'), ('say-as>', 'en'), ('了, 里面有个干尸，不知是被谁<', 'zh'), ("say-as pinyin='gan4'>", 'en'), ('干</', 'zh'), ('say-as>', 'en'), ('死的。</', 'zh'), ('speak>', 'en')]
+        segs = frontend.split_by_lang(text)
+        print(segs)