diff --git a/test/iscsi_tgt/qos/qos.sh b/test/iscsi_tgt/qos/qos.sh
index da12f8f85..5ef493fdb 100755
--- a/test/iscsi_tgt/qos/qos.sh
+++ b/test/iscsi_tgt/qos/qos.sh
@@ -7,25 +7,40 @@ source $rootdir/test/iscsi_tgt/common.sh
 
 function check_qos_works_well() {
 	local enable_limit=$1
-	local iops_limit=$2
+	local qos_limit=$2
 	local retval=0
 
-	start_io_count=$($rpc_py get_bdevs_iostat -b $3 | jq -r '.[1].num_read_ops')
-	$fio_py 512 64 randread 5
-	end_io_count=$($rpc_py get_bdevs_iostat -b $3 | jq -r '.[1].num_read_ops')
+	if [ $LIMIT_TYPE = BANDWIDTH ]; then
+		qos_limit=$((qos_limit*1024*1024))
+	fi
 
-	read_iops=$(((end_io_count-start_io_count)/5))
+	if [ $LIMIT_TYPE = IOPS ]; then
+		start_io_count=$($rpc_py get_bdevs_iostat -b $3 | jq -r '.[1].num_read_ops')
+	else
+		start_io_count=$($rpc_py get_bdevs_iostat -b $3 | jq -r '.[1].bytes_read')
+	fi
+
+	$fio_py 512 64 randread 5
+
+	if [ $LIMIT_TYPE = IOPS ]; then
+		end_io_count=$($rpc_py get_bdevs_iostat -b $3 | jq -r '.[1].num_read_ops')
+	else
+		end_io_count=$($rpc_py get_bdevs_iostat -b $3 | jq -r '.[1].bytes_read')
+	fi
+
+	read_result=$(((end_io_count-start_io_count)/5))
 
 	if [ $enable_limit = true ]; then
-		retval=$(echo "$iops_limit*0.9 < $read_iops && $read_iops < $iops_limit*1.01" | bc)
+		#qos realization is related with bytes transfered.It currently have like 5% variation.
+		retval=$(echo "$qos_limit*0.95 < $read_result && $read_result < $qos_limit*1.05" | bc)
 		if [ $retval -eq 0 ]; then
 			echo "Failed to limit the io read rate of malloc bdev by qos"
 			exit 1
 		fi
 	else
-		retval=$(echo "$read_iops > $iops_limit" | bc)
+		retval=$(echo "$read_result > $qos_limit" | bc)
 		if [ $retval -eq 0 ]; then
-			echo "$read_iops less than $iops_limit - expected greater than"
+			echo "$read_result less than $qos_limit - expected greater than"
 			exit 1
 		fi
 	fi
@@ -46,6 +61,8 @@ timing_enter qos
 MALLOC_BDEV_SIZE=64
 MALLOC_BLOCK_SIZE=512
 IOPS_LIMIT=20000
+BANDWIDTH_LIMIT=10
+LIMIT_TYPE=IOPS
 rpc_py="$rootdir/scripts/rpc.py"
 fio_py="$rootdir/scripts/fio.py"
 
@@ -88,6 +105,20 @@ $rpc_py set_bdev_qos_limit Malloc0 --rw_ios_per_sec $IOPS_LIMIT
 check_qos_works_well true $IOPS_LIMIT Malloc0
 echo "I/O rate limiting tests successful"
 
+# Limit the I/O bandwidth rate by RPC, then confirm the observed rate matches.
+LIMIT_TYPE=BANDWIDTH
+$rpc_py set_bdev_qos_limit Malloc0 --rw_ios_per_sec 0 --rw_mbytes_per_sec $BANDWIDTH_LIMIT
+check_qos_works_well true $BANDWIDTH_LIMIT Malloc0
+
+# Now disable the bandwidth rate limiting, and confirm the observed rate is not limited anymore.
+$rpc_py set_bdev_qos_limit Malloc0 --rw_mbytes_per_sec 0
+check_qos_works_well false $BANDWIDTH_LIMIT Malloc0
+
+# Limit the I/O bandwidth rate again.
+$rpc_py set_bdev_qos_limit Malloc0 --rw_mbytes_per_sec $BANDWIDTH_LIMIT
+check_qos_works_well true $BANDWIDTH_LIMIT Malloc0
+echo "I/O bandwidth limiting tests successful"
+
 iscsicleanup
 $rpc_py delete_target_node 'iqn.2016-06.io.spdk:Target1'