diff --git a/src/inc/taos.h b/src/inc/taos.h
index d6f188357230d2e2f02ce66b0b66c3c74b3c39f0..1d609bc7dbb7f5fe9bc1c26b169fcbdbac973cef 100644
--- a/src/inc/taos.h
+++ b/src/inc/taos.h
@@ -67,8 +67,6 @@ DLL_EXPORT void  taos_init();
 DLL_EXPORT void  taos_cleanup();
 DLL_EXPORT int   taos_options(TSDB_OPTION option, const void *arg, ...);
 DLL_EXPORT TAOS *taos_connect(const char *ip, const char *user, const char *pass, const char *db, uint16_t port);
-DLL_EXPORT TAOS *taos_connect_c(const char *ip, uint8_t ipLen, const char *user, uint8_t userLen,
-                 const char *pass, uint8_t passLen, const char *db, uint8_t dbLen, uint16_t port);
 DLL_EXPORT void  taos_close(TAOS *taos);
 
 typedef struct TAOS_BIND {
@@ -90,7 +88,6 @@ TAOS_RES * taos_stmt_use_result(TAOS_STMT *stmt);
 int        taos_stmt_close(TAOS_STMT *stmt);
 
 DLL_EXPORT TAOS_RES *taos_query(TAOS *taos, const char *sql);
-DLL_EXPORT TAOS_RES *taos_query_c(TAOS *taos, const char *sql, uint32_t sqlLen);
 DLL_EXPORT TAOS_ROW taos_fetch_row(TAOS_RES *res);
 DLL_EXPORT int taos_result_precision(TAOS_RES *res);  // get the time precision of result
 DLL_EXPORT void taos_free_result(TAOS_RES *res);