The flux control speed of ultra fast cooling system in medium and heavy plate can affect the rolling rhythm of the mill, and the flux control accuracy can affect the control accuracy of the plate cooling process. Taking the new ultra fast cooling equipment applied to many medium and heavy plate plant of iron and steel group co as example, the electric valve regulating characteristics was analyzed, the effective method to improve the control speed and accuracy was given, and the reference for the ultra fast cooling equipment and control system design was provided.