The cruise control system (CCS) is an electronic control device that uses advanced electronic technology to automatically adjust the driving speed of the car, so as to realize the constant speed. The vehicle equipped with this system can drive the driver's feet away from the accelerator pedal while driving on a good road, and the car runs at a constant speed selected by the driver. The cruise control system consists of the speed sensor, the cruise control computer (CCECU), the actuator, the main switch and the control switch, the parking brake switch, the brake light switch and the neutral starting switch. The automatic cruising function is easy to relax in the course of driving, and also saves some unnecessary troubles. Automatic cruise system is essential for high gear car.