diff --git a/docs/en/12-taos-sql/10-function.md b/docs/en/12-taos-sql/10-function.md
index 14dedfb216..61648ddaeb 100644
--- a/docs/en/12-taos-sql/10-function.md
+++ b/docs/en/12-taos-sql/10-function.md
@@ -867,6 +867,7 @@ INTERP(expr)
 - The number of rows in the result set of `INTERP` is determined by the parameter `EVERY`. Starting from timestamp1, one interpolation is performed for every time interval specified `EVERY` parameter.
 - Interpolation is performed based on `FILL` parameter.
 - `INTERP` can only be used to interpolate in single timeline. So it must be used with `partition by tbname` when it's used on a STable.
+- Pseudo column `_irowts` can be used along with `INTERP`to return the timestamps associated with interpolation points(support after version 3.0.1.4).
 
 ### LAST
 
diff --git a/docs/zh/12-taos-sql/10-function.md b/docs/zh/12-taos-sql/10-function.md
index 2a4d82045f..a2ef4d02e5 100644
--- a/docs/zh/12-taos-sql/10-function.md
+++ b/docs/zh/12-taos-sql/10-function.md
@@ -868,6 +868,7 @@ INTERP(expr)
 - INTERP 根据 EVERY 字段来确定输出时间范围内的结果条数，即从 timestamp1 开始每隔固定长度的时间（EVERY 值）进行插值。如果没有指定 EVERY，则默认窗口大小为无穷大，即从 timestamp1 开始只有一个窗口。
 - INTERP 根据 FILL 字段来决定在每个符合输出条件的时刻如何进行插值。
 - INTERP 只能在一个时间序列内进行插值，因此当作用于超级表时必须跟 partition by tbname 一起使用。
+- INTERP 可以与伪列_irowts一起使用，返回插值点所对应的时间戳(3.0.1.4版本以后支持)。
 
 ### LAST