diff --git a/ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/StringSubstrColStart.java b/ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/StringSubstrColStart.java
index 3d7742bf1407..146cb0709567 100644
--- a/ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/StringSubstrColStart.java
+++ b/ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/StringSubstrColStart.java
@@ -75,7 +75,7 @@ public StringSubstrColStart() {
    * @param len length of the bytes the string holds in the byte array
    * @param substrStart the Start index for the substring operation
    */
-  static int getSubstrStartOffset(byte[] utf8String, int start, int len, int substrStart) {
+  public static int getSubstrStartOffset(byte[] utf8String, int start, int len, int substrStart) {
     int end = start + len;
 
     if (substrStart < 0) {
diff --git a/ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/StringSubstrColStartLen.java b/ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/StringSubstrColStartLen.java
index 7ef8552123f6..957c46ea6b1b 100644
--- a/ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/StringSubstrColStartLen.java
+++ b/ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/StringSubstrColStartLen.java
@@ -83,10 +83,10 @@ public StringSubstrColStartLen() {
    * @param start start offset of the byte array the string starts at
    * @param len length of the bytes the string holds in the byte array
    * @param substrStart the Start index for the substring operation
-   * @param substrLen the length of the substring
-   * @param offsetArray the array that indexes are populated to. Assume its length >= 2.
+   * @param substrLength the length of the substring
+   * @param offsetArray the array that indexes are populated to. Assume its {@literal length >= 2}.
    */
-  static void populateSubstrOffsets(byte[] utf8String, int start, int len, int substrStart,
+  public static void populateSubstrOffsets(byte[] utf8String, int start, int len, int substrStart,
       int substrLength, int[] offsetArray) {
     int curIdx = -1;
     offsetArray[0] = -1;
diff --git a/ql/src/java/org/apache/hadoop/hive/ql/udf/UDFSubstr.java b/ql/src/java/org/apache/hadoop/hive/ql/udf/UDFSubstr.java
index 7c6de37c8073..419f65778a5c 100755
--- a/ql/src/java/org/apache/hadoop/hive/ql/udf/UDFSubstr.java
+++ b/ql/src/java/org/apache/hadoop/hive/ql/udf/UDFSubstr.java
@@ -96,53 +96,51 @@ private Text evaluateInternal(Text t, int pos, int len) {
       return r;
     }
 
-    String s = t.toString();
-    int[] index = makeIndex(pos, len, s.length());
-    if (index == null) {
+    byte[] utf8String = t.toString().getBytes();
+    StringSubstrColStartLen.populateSubstrOffsets(utf8String, 0, utf8String.length, craetePos(pos), len, index);
+    if (index[0] == -1) {
       return r;
     }
 
-    r.set(s.substring(index[0], index[1]));
+    r.set(new String(utf8String, index[0], index[1]));
     return r;
   }
 
-  private int[] makeIndex(int pos, int len, int inputLen) {
-    if ((Math.abs(pos) > inputLen)) {
-      return null;
-    }
-
-    int start, end;
+  private Text evaluateInternal(Text t, int pos) {
+    r.clear();
 
-    if (pos > 0) {
-      start = pos - 1;
-    } else if (pos < 0) {
-      start = inputLen + pos;
-    } else {
-      start = 0;
+    byte[] utf8String = t.toString().getBytes();
+    int offset = StringSubstrColStart.getSubstrStartOffset(utf8String, 0, utf8String.length, craetePos(pos));
+    if (offset == -1) {
+      return r;
     }
 
-    if ((inputLen - start) < len) {
-      end = inputLen;
-    } else {
-      end = start + len;
-    }
-    index[0] = start;
-    index[1] = end;
-    return index;
+    r.set(new String(utf8String, offset, utf8String.length - offset));
+    return r;
   }
 
-  private final IntWritable maxValue = new IntWritable(Integer.MAX_VALUE);
-
-  // Even though we are using longs, substr can only deal with ints, so we use
-  // the maximum int value as the maxValue
-  private final LongWritable maxLongValue = new LongWritable(Integer.MAX_VALUE);
-
   public Text evaluate(Text s, IntWritable pos) {
-    return evaluate(s, pos, maxValue);
+    if ((s == null) || (pos == null)) {
+      return null;
+    }
+
+    return evaluateInternal(s, pos.get());
   }
 
   public Text evaluate(Text s, LongWritable pos) {
-    return evaluate(s, pos, maxLongValue);
+    if ((s == null) || (pos == null)) {
+      return null;
+    }
+
+    long longPos = pos.get();
+    // If an unsupported value is seen, we don't want to return a string
+    // that doesn't match what the user expects, so we return NULL (still
+    // unexpected, of course, but probably better than a bad string).
+    if (longPos > Integer.MAX_VALUE || longPos < Integer.MIN_VALUE) {
+      return null;
+    }
+
+    return evaluateInternal(s, (int) pos.get());
   }
 
   public BytesWritable evaluate(BytesWritable bw, LongWritable pos, LongWritable len) {
@@ -172,25 +170,42 @@ public BytesWritable evaluate(BytesWritable bw, IntWritable pos, IntWritable len
   }
 
   private BytesWritable evaluateInternal(BytesWritable bw, int pos, int len) {
-
     if (len <= 0) {
       return new BytesWritable();
     }
 
-    int[] index = makeIndex(pos, len, bw.getLength());
-    if (index == null) {
+    byte[] b = Arrays.copyOf(bw.getBytes(), bw.getLength());
+    StringSubstrColStartLen.populateSubstrOffsets(b, 0, b.length, craetePos(pos), len, index);
+    if (index[0] == -1) {
       return new BytesWritable();
     }
 
-    return new BytesWritable(Arrays.copyOfRange(bw.getBytes(), index[0], index[1]));
+    return new BytesWritable(arrayCopy(b, index[0], index[1]));
+  }
+
+  private BytesWritable evaluateInternal(BytesWritable bw, int pos) {
+    byte[] b = Arrays.copyOf(bw.getBytes(), bw.getLength());
+    int offset = StringSubstrColStart.getSubstrStartOffset(b, 0, b.length, craetePos(pos));
+    if (offset == -1) {
+      return new BytesWritable();
+    }
+
+    return new BytesWritable(arrayCopy(b, offset, bw.getLength() - offset));
   }
 
   public BytesWritable evaluate(BytesWritable bw, IntWritable pos){
-    return evaluate(bw, pos, maxValue);
+    if ((bw == null) || (pos == null)) {
+      return null;
+    }
+    return evaluateInternal(bw, pos.get());
   }
 
   public BytesWritable evaluate(BytesWritable bw, LongWritable pos){
-    return evaluate(bw, pos, maxLongValue);
+    if ((bw == null) || (pos == null)) {
+      return null;
+    }
+
+    return evaluateInternal(bw, (int) pos.get());
   }
 
   @Override
@@ -198,6 +213,26 @@ public StatEstimator getStatEstimator() {
     return new SubStrStatEstimator();
   }
 
+  private byte[] arrayCopy(byte[] src, int pos, int len) {
+    byte[] b = new byte[len];
+
+    int copyIdx = 0;
+    for (int srcIdx = pos; copyIdx < len; srcIdx++) {
+      b[copyIdx] = src[srcIdx];
+      copyIdx++;
+    }
+
+    return b;
+  }
+
+  private int craetePos(int pos) {
+    if (pos <= 0) {
+      return pos;
+    }
+
+    return pos - 1;
+  }
+
   private static class SubStrStatEstimator implements StatEstimator {
 
     @Override
diff --git a/ql/src/test/queries/clientpositive/udf_substr.q b/ql/src/test/queries/clientpositive/udf_substr.q
index a609536f37e5..f1ea68d99c5b 100644
--- a/ql/src/test/queries/clientpositive/udf_substr.q
+++ b/ql/src/test/queries/clientpositive/udf_substr.q
@@ -89,3 +89,11 @@ FROM src tablesample (1 rows);
 SELECT
   substr('ABC', cast(2147483649 as bigint))
 FROM src tablesample (1 rows);
+
+--test 4-byte charactor
+set hive.vectorized.execution.enabled=false;
+SELECT
+  substr('あa🤎いiうu', 1, 3) as b1,
+  substr('あa🤎いiうu', 3) as b2,
+  substr('あa🤎いiうu', -5) as b3
+FROM src tablesample (1 rows);
diff --git a/ql/src/test/results/clientpositive/llap/udf_substr.q.out b/ql/src/test/results/clientpositive/llap/udf_substr.q.out
index 9ffa39b03356..ebf541a31e6d 100644
--- a/ql/src/test/results/clientpositive/llap/udf_substr.q.out
+++ b/ql/src/test/results/clientpositive/llap/udf_substr.q.out
@@ -240,3 +240,20 @@ POSTHOOK: type: QUERY
 POSTHOOK: Input: default@src
 #### A masked pattern was here ####
 NULL
+PREHOOK: query: SELECT
+  substr('あa🤎いiうu', 1, 3) as b1,
+  substr('あa🤎いiうu', 3) as b2,
+  substr('あa🤎いiうu', -5) as b3
+FROM src tablesample (1 rows)
+PREHOOK: type: QUERY
+PREHOOK: Input: default@src
+#### A masked pattern was here ####
+POSTHOOK: query: SELECT
+  substr('あa🤎いiうu', 1, 3) as b1,
+  substr('あa🤎いiうu', 3) as b2,
+  substr('あa🤎いiうu', -5) as b3
+FROM src tablesample (1 rows)
+POSTHOOK: type: QUERY
+POSTHOOK: Input: default@src
+#### A masked pattern was here ####
+あa🤎	🤎いiうu	🤎いiうu