To increase control precision and improve dynamic characteristic of continuously variable transmission control system, a method of processing data called optimal test that usually adopted in chemical experiment is applied. After parameters are ensured, the critical gain KV of the open-loop system is determined by the stability, then the factors are determined and the orthogonal table is constituted to try out. In the end, the dynamic characteristics of the system are simulated by SIMULINK software. Thus the optimum PID parameters can be achieved. Through the method above, we can avoid a lot of complex trials which determine PID parameters and get better control effect. It is shown by simulation that the PID rectification for CVT control system using Optimal test increases fairly control precision, rapidity of step response and make the quality of the control system best.