diff --git a/backends-velox/src/test/scala/org/apache/gluten/execution/ScalarFunctionsValidateSuite.scala b/backends-velox/src/test/scala/org/apache/gluten/execution/ScalarFunctionsValidateSuite.scala
index adb8be51d66ec..cb1d63c90a5a7 100644
--- a/backends-velox/src/test/scala/org/apache/gluten/execution/ScalarFunctionsValidateSuite.scala
+++ b/backends-velox/src/test/scala/org/apache/gluten/execution/ScalarFunctionsValidateSuite.scala
@@ -1235,39 +1235,4 @@ class ScalarFunctionsValidateSuite extends FunctionsValidateTest {
       checkGlutenOperatorMatch[ProjectExecTransformer]
     }
   }
-
-  test("Test substring_index") {
-    withTempView("substring_index_table") {
-      withTempPath {
-        path =>
-          Seq[(String, String, Int)](
-            ("www.apache.org", ".", 3),
-            ("www.apache.org", ".", 2),
-            ("www.apache.org", ".", 1),
-            ("www.apache.org", ".", 0),
-            ("www.apache.org", ".", -1),
-            ("www.apache.org", ".", -2),
-            ("www.apache.org", ".", -3),
-            ("www.apache.org", "", 1),
-            ("www.apache.org", "#", 1),
-            ("www||apache||org", "||", 2),
-            ("www||apache||org", "||", -2),
-            ("", ".", 1),
-            ("||||||", "|||", 3),
-            ("||||||", "|||", -4)
-          )
-            .toDF("str", "delim", "count")
-            .write
-            .parquet(path.getCanonicalPath)
-          spark.read.parquet(path.getCanonicalPath).createOrReplaceTempView("substring_index_table")
-          runQueryAndCompare(
-            """
-              |select substring_index(str, delim, count) from substring_index_table
-              |""".stripMargin
-          ) {
-            checkGlutenOperatorMatch[ProjectExecTransformer]
-          }
-      }
-    }
-  }
 }
diff --git a/docs/velox-backend-support-progress.md b/docs/velox-backend-support-progress.md
index 8429759fa381b..47fc68e4c0fe5 100644
--- a/docs/velox-backend-support-progress.md
+++ b/docs/velox-backend-support-progress.md
@@ -185,7 +185,7 @@ Gluten supports 199 functions. (Drag to right to see all data types)
 | startswith                    |                        | startsWith            |        |                          |         |      |       |     |      |       |        |      |           |        |         |      |        |          |       |     |        |     |
 | substr, substring             | substr                 | substring             | S      |                          |         |      |       |     |      |       |        |      |           | S      |         |      |        |          |       |     |        |     |
 | substring, substr             | substr                 | substring             | S      |                          |         |      |       |     |      |       |        |      |           | S      |         |      |        |          |       |     |        |     |
-| substring_index               |                        | substring_index       | S      |                          |         |      |       |     |      |       |        |      |           |        |         |      |        |          |       |     |        |     |
+| substring_index               |                        |                       |        |                          |         |      |       |     |      |       |        |      |           |        |         |      |        |          |       |     |        |     |
 | translate                     |                        |                       |        |                          |         |      |       |     |      |       |        |      |           |        |         |      |        |          |       |     |        |     |
 | trim                          | trim                   | trim                  | S      |                          |         |      |       |     |      |       |        |      |           | S      |         |      |        |          |       |     |        |     |
 | ucase, upper                  | upper                  | upper                 | S      |                          |         |      |       |     |      |       |        |      |           | S      |         |      |        |          |       |     |        |     |