Abstract: Aiming at the problems of slow speed of guide vane opening and active power regulation, susceptible to water hammer reaction and unit inertia during regulation process of hydro-generator unit under open mode power closed-loop control, this paper puts forward a new open-loop and sectional open-loop control method of guide vane opening based on opening mode of turbine monitoring system step by step.The structure model and control principle of open-loop and sectional open-loop control of guide vane in opening mode are elaborated, and three control methods of guide vane opening in opening mode are modeled and simulated by using matlab. By comparing and analyzing the simulation results, it is found that the sectional open-loop control method of guide vane opening analogue of turbine monitoring system has the best performance. It not only has the characteristics of fast open-loop control, but also has the advantage of small overshoot of sectional open-loop control. It can effectively solve the problems of water hammer reaction and unit inertia action during guide vane opening and active power regulation of turbine-generator unit.