diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 968d62d939..95af35c567 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -5382,6 +5382,7 @@ int32_t validateFillNode(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SSqlNode* pSqlNo
   const char* msg3 = "top/bottom not support fill";
   const char* msg4 = "illegal value or data overflow";
   const char* msg5 = "fill only available for interval query";
+  const char* msg6 = "not supported function now";
 
   if ((!isTimeWindowQuery(pQueryInfo)) && (!tscIsPointInterpQuery(pQueryInfo))) {
     return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg5);
@@ -5420,6 +5421,9 @@ int32_t validateFillNode(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SSqlNode* pSqlNo
     }
   } else if (strncasecmp(pItem->pVar.pz, "prev", 4) == 0 && pItem->pVar.nLen == 4) {
     pQueryInfo->fillType = TSDB_FILL_PREV;
+    if (tscIsPointInterpQuery(pQueryInfo) && pQueryInfo->order.order == TSDB_ORDER_DESC) {
+      return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg6);
+    }
   } else if (strncasecmp(pItem->pVar.pz, "next", 4) == 0 && pItem->pVar.nLen == 4) {
     pQueryInfo->fillType = TSDB_FILL_NEXT;
   } else if (strncasecmp(pItem->pVar.pz, "linear", 6) == 0 && pItem->pVar.nLen == 6) {
diff --git a/tests/pytest/functions/function_interp.py b/tests/pytest/functions/function_interp.py
index 810c90279c..41215f15eb 100644
--- a/tests/pytest/functions/function_interp.py
+++ b/tests/pytest/functions/function_interp.py
@@ -26,18 +26,70 @@ class TDTestCase:
 
         self.rowNum = 10
         self.ts = 1537146000000
-        
+
     def run(self):
         tdSql.prepare()
-        tdSql.execute("create table t(ts timestamp, k int)")
-        tdSql.execute("insert into t values('2021-1-1 1:1:1', 12);")
-        
-        tdSql.query("select interp(*) from t where ts='2021-1-1 1:1:1'")
-        tdSql.checkRows(1)
-        tdSql.checkData(0, 1, 12)
+        tdSql.execute("create table ap1 (ts timestamp, pav float)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:54.119', 2.90799)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:54.317', 3.07399)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:54.517', 0.58117)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:54.717', 0.16150)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:54.918', 1.47885)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:56.569', 1.76472)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:57.381', 2.13722)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:57.574', 4.10256)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:57.776', 3.55345)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:57.976', 1.46624)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:58.187', 0.17943)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:58.372', 2.04101)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:58.573', 3.20924)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:58.768', 1.71807)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:58.964', 4.60900)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:59.155', 4.33907)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:59.359', 0.76940)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:59.553', 0.06458)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:59.742', 4.59857)")
+        tdSql.execute("insert into ap1 values ('2021-07-25 02:19:59.938', 1.55081)")
+
+        tdSql.query("select interp(pav) from ap1 where ts = '2021-07-25 02:19:54' FILL (PREV)")
+        tdSql.checkRows(0)
+        tdSql.query("select interp(pav) from ap1 where ts = '2021-07-25 02:19:54' FILL (NEXT)")
+        tdSql.checkRows(0)
+        tdSql.query("select interp(pav) from ap1 where ts = '2021-07-25 02:19:54' FILL (LINEAR)")
+        tdSql.checkRows(0)
+        tdSql.query("select interp(pav) from ap1 where ts> '2021-07-25 02:19:54' and ts<'2021-07-25 02:20:00' INTERVAL(1000a) FILL (LINEAR)")
+        tdSql.checkRows(6)
+        tdSql.query("select interp(pav) from ap1 where ts>= '2021-07-25 02:19:54' and ts<'2021-07-25 02:20:00' INTERVAL(1000a) FILL (NEXT)")
+        tdSql.checkRows(6)
+        tdSql.checkData(0,1,2.90799)
+        tdSql.query("select interp(pav) from ap1 where ts> '2021-07-25 02:19:54' and ts <= '2021-07-25 02:20:00' INTERVAL(1000a) FILL (PREV)")
+        tdSql.checkRows(7)
+        tdSql.checkData(1,1,1.47885)
+        tdSql.query("select interp(pav) from ap1 where ts>= '2021-07-25 02:19:54' and ts <= '2021-07-25 02:20:00' INTERVAL(1000a) FILL (LINEAR)")
+        tdSql.checkRows(7)
+
+        # check desc order
+        tdSql.error("select interp(pav) from ap1 where ts = '2021-07-25 02:19:54' FILL (PREV) order by ts desc")
+        tdSql.query("select interp(pav) from ap1 where ts = '2021-07-25 02:19:54' FILL (NEXT) order by ts desc")
+        tdSql.checkRows(0)
+        tdSql.query("select interp(pav) from ap1 where ts = '2021-07-25 02:19:54' FILL (LINEAR) order by ts desc")
+        tdSql.checkRows(0)
+        tdSql.query("select interp(pav) from ap1 where ts> '2021-07-25 02:19:54' and ts<'2021-07-25 02:20:00' INTERVAL(1000a) FILL (LINEAR) order by ts desc")
+        tdSql.checkRows(6)
+        tdSql.query("select interp(pav) from ap1 where ts>= '2021-07-25 02:19:54' and ts<'2021-07-25 02:20:00' INTERVAL(1000a) FILL (NEXT) order by ts desc")
+        tdSql.checkRows(6)
+        tdSql.checkData(0,1,4.60900)
+        tdSql.error("select interp(pav) from ap1 where ts> '2021-07-25 02:19:54' and ts <= '2021-07-25 02:20:00' INTERVAL(1000a) FILL (PREV) order by ts desc")
+        tdSql.query("select interp(pav) from ap1 where ts>= '2021-07-25 02:19:54' and ts <= '2021-07-25 02:20:00' INTERVAL(1000a) FILL (LINEAR) order by ts desc")
+        tdSql.checkRows(7)
+
+        # check exception
+        tdSql.error("select interp(*) from ap1")
+        tdSql.error("select interp(*) from ap1 FILL(NEXT)")
+        tdSql.error("select interp(*) from ap1 ts >= '2021-07-25 02:19:54' FILL(NEXT)")
+        tdSql.error("select interp(*) from ap1 ts <= '2021-07-25 02:19:54' FILL(NEXT)")
+        tdSql.error("select interp(*) from ap1 where ts >'2021-07-25 02:19:59.938' and ts < now interval(1s) fill(next)")
 
-        tdSql.error("select interp(*) from t where ts >'2021-1-1 1:1:1' and ts < now interval(1s) fill(next)")
- 
     def stop(self):
         tdSql.close()
         tdLog.success("%s successfully executed" % __file__)