Aiming at the problems of excessive overshoot and slow response speed when the engine enters the idling state,this paper proposes a Runge-Kutta predictive adaptive PID algorithm to control the idling speed of the hybrid electric vehicle engine.First,Runge-Kutta is used to predict and calculate the system state,and the next step is to obtain the predicted output of the system.Then the deviation signal between the set value and the predicted output value is obtained,combined with the optimal gradient descent method to modify the PID parameters online,so that the system is realized.The purpose of pre-adjustment to quickly enter the engine idling state will also help reduce the fuel consumption of the vehicle.From the final simulation results,overshoot and response time have been greatly improved,thus verifying the effectiveness and feasibility of the method.