Abstract: With the measured values of openings of all solenoid regulating values and relevant conduit flows sampled, calculated and analyzed, a curve of setting values of water flowrate in relation to the opening value is given. Then, based on the curve, the primary water output from flow controller is worked out and a closed-loop control is provided by PID controller to modify the deviation of flowmeter feedback from the setting value of water flowrate. Thus, the control accuracy of cooling water flowrate can be improved. The results show that such a flow control technique is successful in actual rolling process.