The Adaptive Cruise Control system can assist the driver to adjust the size of the vehicle throttle opening and the pressure of the brake pedal to achieve the vehicle's following cruise. In this paper, the hierarchical control scheme is selected in the design of ACC system. The upper control system is based on the vehicle safety distance model built by the headway strategy to obtain the expected safety distance. Then, through the MPC algorithm, the discrete state space model of longitudinal following is established, and the system performance index and constraints are established. The problem is transformed into a constrained quadratic programming problem, and the expected acceleration of the vehicle is calculated. The lower control system constructs the vehicle longitudinal dynamics model, builds the engine reverse power model and the inverse model of the braking system, and determines the driving and braking conversion logic to realize the acceleration and deceleration of the vehicle. After that, using Carsim and MATLAB/Simulink for joint simulation verification, it can be concluded that the designed ACC system can realize the functions of following cruise. It can complete acceleration and deceleration to the target speed in a short time, and ensure that the acceleration is small to meet the comfort requirements, reduce traffic accidents, and improve vehicle driving safety and comfort.