Abstract: The function of active braking in the adaptive cruise control system was discussed, the strategy based on acceleration control was employed and the configuration of the active braking system was introduced. In order to calculate the desired braking pressure, a converse vehicle braking model was built based on the dynamic analysis and experiments. Using the improved PID control algorithm, the pressure controller has been developed. Experiments indicate that both the pressure and acceleration control meet the requirements of adaptive cruise control system for active braking control.