A new type of digital trigger control system on the base of Singlechip Controller is proposed for water power station control system. The trigger use the singlechip controller's highspeed output port skillfully, and this system included controller and trigger,so as to reduce the component, reduce the cost and make the system more integrated, more precise and more reliable and advanced the hydro excitation control system. In this system, we use new electric technology, new detection technology and new automatic theory, so as to make the system more perfect and more intelligent. It has overcome the disadvantage of simulation integrate circuit in above.