Three-Phase asynchronous motor’s power factor and efficiency are usually very low when the loads are free or light. Regulating the input voltage of motors properly can raise the power factor and reduce the losses, which is a kind of Energy-saving technology. This paper introduces an adaptive control method of three-phase asynchronous motors which is a kind of energy-saving technology based on R8CL38. The reference model with optimum control method is adopted. It can control the voltage of three-phase asynchronous motors directly. Simulation results show the designed energy-saving power controller is effective, and the control system is stable and reliable.