diff --git a/src/tarina/_string_c.pyx b/src/tarina/_string_c.pyx
index 07501d7..cc978fd 100644
--- a/src/tarina/_string_c.pyx
+++ b/src/tarina/_string_c.pyx
@@ -9,6 +9,7 @@ from cpython.unicode cimport (
     PyUnicode_Join,
     PyUnicode_Split,
     PyUnicode_Substring,
+    PyUnicode_Concat,
 )
 
 
@@ -28,6 +29,8 @@ cdef dict QUOTES = {'"': '"', "'": "'"}
 cdef unicode CRLF = "\n\r"
 
 cpdef inline list split(str text, str separator, bint crlf=True):
+    if crlf:
+        separator = PyUnicode_Concat(separator, CRLF)
     text = str_strip(text, BOTHSTRIP, separator)
     cdef:
         bint escape = 0
@@ -55,7 +58,7 @@ cpdef inline list split(str text, str separator, bint crlf=True):
                 PyList_Append(result, ch)
             if escape:
                 result[PyList_GET_SIZE(result)-1] = ch
-        elif str_contains(separator, ch) or (crlf and str_contains(CRLF, ch)):
+        elif str_contains(separator, ch):
             if quotation:
                 PyList_Append(quoted_sep_index, PyList_GET_SIZE(result) + 1)
                 PyList_Append(result, ch)
@@ -79,6 +82,8 @@ cpdef inline list split(str text, str separator, bint crlf=True):
 
 
 cpdef inline tuple split_once(str text, str separator, bint crlf=True):
+    if crlf:
+        separator = PyUnicode_Concat(separator, CRLF)
     text = str_strip(text, LEFTSTRIP, separator)
     cdef:
         Py_ssize_t index = 0
@@ -93,7 +98,7 @@ cpdef inline tuple split_once(str text, str separator, bint crlf=True):
     while index < length:
         ch = PyUnicode_READ_CHAR(text, index)
         index += 1
-        if str_contains(separator, ch) or (crlf and str_contains(CRLF, ch)):
+        if str_contains(separator, ch):
             if quotation == 0:
                 sep = 1
                 continue
diff --git a/src/tarina/_string_py.py b/src/tarina/_string_py.py
index c1fb182..59e1ee3 100644
--- a/src/tarina/_string_py.py
+++ b/src/tarina/_string_py.py
@@ -15,6 +15,8 @@ def split_once(text: str, separator: str, crlf: bool = True):
     Returns:
         Tuple[str, str]: 切割后的字符串, 可能含有空格
     """
+    if crlf:
+        separator += CRLF
     index, out_text, quotation, escape, sep = 0, "", "", False, False
     text = text.lstrip()
     first_quoted_sep_index = -1
@@ -22,7 +24,7 @@ def split_once(text: str, separator: str, crlf: bool = True):
     tlen = len(text)
     for char in text:
         index += 1
-        if char in separator or (crlf and char in CRLF):
+        if char in separator:
             if not quotation:
                 sep = True
                 continue
@@ -63,6 +65,8 @@ def split(text: str, separator: str, crlf: bool = True):
     Returns:
         List[str]: 切割后的字符串, 可能含有空格
     """
+    if crlf:
+        separator += CRLF
     text = text.strip(separator)
     result, quotation, escape = [], "", False
     quoted_sep_index = []
@@ -81,7 +85,7 @@ def split(text: str, separator: str, crlf: bool = True):
                 result.append(char)
             if escape:
                 result[-1] = char
-        elif char in separator or (crlf and char in CRLF):
+        elif char in separator:
             if quotation:
                 quoted_sep_index.append(len(result) + 1)
                 result.append(char)