diff --git a/paddlespeech/t2s/frontend/mix_frontend.py b/paddlespeech/t2s/frontend/mix_frontend.py
index 6868d335..a681445c 100644
--- a/paddlespeech/t2s/frontend/mix_frontend.py
+++ b/paddlespeech/t2s/frontend/mix_frontend.py
@@ -61,7 +61,8 @@ class MixFrontend():
             return False
 
     def is_end(self, before_char, after_char) -> bool:
-        if ((self.is_alphabet(before_char) or before_char == " ") and (self.is_alphabet(after_char) or after_char == " ")):
+        if ((self.is_alphabet(before_char) or before_char == " ") and
+            (self.is_alphabet(after_char) or after_char == " ")):
             return True
         else:
             return False
@@ -86,10 +87,11 @@ class MixFrontend():
             if point_index == 0 or point_index == len(text) - 1:
                 new_text = text
             else:
-                if not self.is_end(text[point_index - 1], text[point_index + 1]):
+                if not self.is_end(text[point_index - 1], text[point_index +
+                                                               1]):
                     new_text = text
                 else:
-                    new_text = text[: point_index] + "。" + text[point_index + 1:]
+                    new_text = text[:point_index] + "。" + text[point_index + 1:]
 
         elif len(point_indexs) == 2:
             first_index = point_indexs[0]
@@ -97,7 +99,8 @@ class MixFrontend():
 
             # first
             if first_index != 0:
-                if not self.is_end(text[first_index - 1], text[first_index + 1]):
+                if not self.is_end(text[first_index - 1], text[first_index +
+                                                               1]):
                     new_text += (text[:first_index] + ".")
                 else:
                     new_text += (text[:first_index] + "。")
@@ -106,18 +109,20 @@ class MixFrontend():
             # last
             if end_index != len(text) - 1:
                 if not self.is_end(text[end_index - 1], text[end_index + 1]):
-                    new_text += text[point_indexs[-2] + 1 : ]
+                    new_text += text[point_indexs[-2] + 1:]
                 else:
-                    new_text += (text[point_indexs[-2] + 1 : end_index] + "。" + text[end_index + 1 : ])
+                    new_text += (text[point_indexs[-2] + 1:end_index] + "。" +
+                                 text[end_index + 1:])
             else:
-                new_text += "."          
+                new_text += "."
 
         else:
             first_index = point_indexs[0]
             end_index = point_indexs[-1]
             # first
             if first_index != 0:
-                if not self.is_end(text[first_index - 1], text[first_index + 1]):
+                if not self.is_end(text[first_index - 1], text[first_index +
+                                                               1]):
                     new_text += (text[:first_index] + ".")
                 else:
                     new_text += (text[:first_index] + "。")
@@ -126,16 +131,20 @@ class MixFrontend():
             # middle
             for j in range(1, len(point_indexs) - 1):
                 point_index = point_indexs[j]
-                if not self.is_end(text[point_index - 1], text[point_index + 1]):
-                    new_text += (text[point_indexs[j-1] + 1 : point_index] + ".")
+                if not self.is_end(text[point_index - 1], text[point_index +
+                                                               1]):
+                    new_text += (
+                        text[point_indexs[j - 1] + 1:point_index] + ".")
                 else:
-                    new_text += (text[point_indexs[j-1] + 1 : point_index] + "。")
+                    new_text += (
+                        text[point_indexs[j - 1] + 1:point_index] + "。")
             # last
             if end_index != len(text) - 1:
                 if not self.is_end(text[end_index - 1], text[end_index + 1]):
-                    new_text += text[point_indexs[-2] + 1 : ]
+                    new_text += text[point_indexs[-2] + 1:]
                 else:
-                    new_text += (text[point_indexs[-2] + 1 : end_index] + "。" + text[end_index + 1 : ])
+                    new_text += (text[point_indexs[-2] + 1:end_index] + "。" +
+                                 text[end_index + 1:])
             else:
                 new_text += "."
 
@@ -224,7 +233,7 @@ class MixFrontend():
 
     def get_input_ids(self,
                       sentence: str,
-                      merge_sentences: bool=True,
+                      merge_sentences: bool=False,
                       get_tone_ids: bool=False,
                       add_sp: bool=True,
                       to_tensor: bool=True) -> Dict[str, List[paddle.Tensor]]:
@@ -232,28 +241,29 @@ class MixFrontend():
         sentences = self._split(sentence)
         phones_list = []
         result = {}
-
         for text in sentences:
             phones_seg = []
             segments = self._distinguish(text)
             for seg in segments:
                 content = seg[0]
                 lang = seg[1]
-                if lang == "zh":
-                    input_ids = self.zh_frontend.get_input_ids(
-                        content,
-                        merge_sentences=True,
-                        get_tone_ids=get_tone_ids,
-                        to_tensor=to_tensor)
-
-                elif lang == "en":
-                    input_ids = self.en_frontend.get_input_ids(
-                        content, merge_sentences=True, to_tensor=to_tensor)
-
-                phones_seg.append(input_ids["phone_ids"][0])
-                if add_sp:
-                    phones_seg.append(self.sp_id_tensor)
-
+                if content != '':
+                    if lang == "en":
+                        input_ids = self.en_frontend.get_input_ids(
+                            content, merge_sentences=True, to_tensor=to_tensor)
+                    else:
+                        input_ids = self.zh_frontend.get_input_ids(
+                            content,
+                            merge_sentences=True,
+                            get_tone_ids=get_tone_ids,
+                            to_tensor=to_tensor)
+
+                    phones_seg.append(input_ids["phone_ids"][0])
+                    if add_sp:
+                        phones_seg.append(self.sp_id_tensor)
+
+            if phones_seg == []:
+                phones_seg.append(self.sp_id_tensor)
             phones = paddle.concat(phones_seg)
             phones_list.append(phones)