Abstract: The description concerns the speed-monitoring unit of the control system for the non-tail-end loss arrangement of the Assel pipe mill located at 170 Seamless Steel Tube Plant,Yegang Group Co.,covering configuration,working principle and the setting process. Relevant operational practice has proven that the control system is able to ensure the overall control accuracy by means of compensating the expected calculated value error of the speed-monitoring unit with both hard and soft wares.