Abstract: In the practical teaching of mechatronical control technology,the closed-loop control law design of mechatronical object model is difficult to be understood by students.In this paper,a valve control of hydraulic cylinder construction with feedback control loop is constructed by MATLAB SISO(single input single output)tool.Furthermore,the PI control law form and the corresponding control parameters are optimally designed.Through the intuitive data of step response and the simulation result of the stable margin in frequency domain,students can achieve deep comprehension of mechatronics plant model,PI control law design and stability of feedback control loop.The idea proposed in this study can inspire students’ learning interests and improve the capability of practical innovation.