Aiming at a certain motorcycle type equipped with the metal-belt continuously variable transmission（CVT）

target rotation speed adjustment characteristics of its engine is established.The aimed speed ratio of CVT is calculated

the mathematical model of hydraulic control and execution system of CVT is created.Considering time variable nonlinear and the time lag coupling features of speed ratio control

according to the immune feedback principle in the biological immune system and the advantages of both fuzzy and PID control

a fuzzy immune PID speed ratio controller is designed.The start-up

acceleration and gradient conditions of CVT complete vehicle model simulation analysis are carried out in simulink conditions.The results show that the fuzzy immune PID speed ratio control can track the target speed ratio well and has a good dynamic response and high control accuracy of steady state.