Abstract: To relieve driver's workload and improve driving safety and comfort, an algorithm with hierarchically configured architecture of adaptive cruise control (ACC) is proposed and it has been applied to vehicle by regulating the electronic throttle. In the upper layer control, a linear control algorithm depended on driver's steady car-following behavior and an alternative safe headway model was designed. In the bottom layer, the closed-loop velocity control strategy was constructed based on inverse query table. The throttle angle look-up table was set-up based on the knowledge acquired from vehicle test and precise velocity adjustment was applied with the increasing mode of PID control. Eventually, the good effect of velocity following was achieved. The cruise control and steady car-following experiments were implemented to verify the effectiveness of proposed control algorithm. The result shows that, the developed ACC controller can mitigate driving fatigue in normal driving situations effectively and has good performance of acceptance and comfort to driver.