diff --git a/f2/utils/utils.py b/f2/utils/utils.py
index 81ee8e9..9eb7b44 100644
--- a/f2/utils/utils.py
+++ b/f2/utils/utils.py
@@ -927,7 +927,7 @@ def aes_encrypt(self, plaintext: bytes) -> bytes:
         elif self.mode == "ECB":
             return self._aes_encrypt_ecb(plaintext)
 
-    def aes_decrypt(self, ciphertext: bytes) -> bytes:
+    def aes_decrypt(self, ciphertext: bytes, iv: Optional[bytes] = None) -> bytes:
         """
         AES 解密
 
@@ -940,7 +940,7 @@ def aes_decrypt(self, ciphertext: bytes) -> bytes:
         if self.mode == "GCM":
             return self._aes_decrypt_gcm(ciphertext)
         elif self.mode == "CBC":
-            return self._aes_decrypt_cbc(ciphertext)
+            return self._aes_decrypt_cbc(ciphertext, iv)
         elif self.mode == "ECB":
             return self._aes_decrypt_ecb(ciphertext)
 
@@ -990,17 +990,14 @@ def _aes_encrypt_cbc(self, plaintext: bytes) -> bytes:
         ciphertext = encryptor.update(padded_data) + encryptor.finalize()
         return ciphertext  # 返回密文
 
-    def _aes_decrypt_cbc(self, ciphertext: bytes) -> bytes:
+    def _aes_decrypt_cbc(self, ciphertext: bytes, iv: bytes) -> bytes:
         """CBC模式解密"""
-        iv = ciphertext[:16]  # 获取 IV（16 字节）
-        ciphertext_data = ciphertext[16:]  # 获取密文
-
         cipher = Cipher(
             algorithms.AES(self.key), modes.CBC(iv), backend=default_backend()
         )
         decryptor = cipher.decryptor()
 
-        padded_plaintext = decryptor.update(ciphertext_data) + decryptor.finalize()
+        padded_plaintext = decryptor.update(ciphertext) + decryptor.finalize()
 
         # 去除填充
         unpadder = aes_padding.PKCS7(128).unpadder()
diff --git a/tests/test_aes.py b/tests/test_aes.py
index 60f9c24..b454270 100644
--- a/tests/test_aes.py
+++ b/tests/test_aes.py
@@ -79,7 +79,7 @@ def test_aes128_gcm_encrypt_decrypt(aes128_gcm_encryption):
 # 测试 AES128 CBC 加密和解密
 def test_aes128_cbc_encrypt_decrypt(aes128_cbc_encryption):
     encrypted = aes128_cbc_encryption.aes_encrypt(TEST_TEXT)
-    decrypted = aes128_cbc_encryption.aes_decrypt(encrypted)
+    decrypted = aes128_cbc_encryption.aes_decrypt(encrypted, iv=TEST_IV_CBC)
 
     assert decrypted == TEST_TEXT, "AES128 CBC 解密失败，明文不匹配"
 
@@ -103,7 +103,7 @@ def test_aes192_gcm_encrypt_decrypt(aes192_gcm_encryption):
 # 测试 AES192 CBC 加密和解密
 def test_aes192_cbc_encrypt_decrypt(aes192_cbc_encryption):
     encrypted = aes192_cbc_encryption.aes_encrypt(TEST_TEXT)
-    decrypted = aes192_cbc_encryption.aes_decrypt(encrypted)
+    decrypted = aes192_cbc_encryption.aes_decrypt(encrypted, iv=TEST_IV_CBC)
 
     assert decrypted == TEST_TEXT, "AES192 CBC 解密失败，明文不匹配"
 
@@ -127,7 +127,7 @@ def test_aes256_gcm_encrypt_decrypt(aes256_gcm_encryption):
 # 测试 AES256 CBC 加密和解密
 def test_aes256_cbc_encrypt_decrypt(aes256_cbc_encryption):
     encrypted = aes256_cbc_encryption.aes_encrypt(TEST_TEXT)
-    decrypted = aes256_cbc_encryption.aes_decrypt(encrypted)
+    decrypted = aes256_cbc_encryption.aes_decrypt(encrypted, iv=TEST_IV_CBC)
 
     assert decrypted == TEST_TEXT, "AES256 CBC 解密失败，明文不匹配"