An active vibration absorber mounted on rotor hub is introduced. Based on the movement characteristic of eccentric masses of the vibration absorber, the DC motor is chosen as driver, the simulation model of active vibration absorber is established, and its operating principle is studied. When the output force of vibration absorber is changing, the angular velocity is optimized in the transitional stage, thus guaranteeing the small change of output force and required power. The simulation of output force transitional stage of an active vibration absorber is carried out. The results show that the control algorithm can complete the transitional stage within a short time, achieving the aim of decreasing the load of rotor hub ultimately.