This paper describes the feasibility of unity power factor operation for three-phase induction motor subjected to variable loads. In this paper a shunt active power filter is used to provide such operation. The principle of operation is introduced. The two-loop control strategy is used to analyze. From simulation results it is clear that, under all loading conditions, the power factor is achieved unity automatically. Furthermore, the supply current can be obtained sinusoidal. A system based on microcontroller has been tested in the lab to confirm the analysis. The experimental results show that this method to improve power factor of motor is feasible.