Aiming at the features of complexity, poor real-time and Low-accuracy of single-phase Active Power Filter (APF), and the problem of impossible parallel computation in the traditional DSP software realization, new design method of APF Based on FPGA is proposed, This paper focuses on the study of the harmonic current detecting method and improves control method of compensate current, it builds an experimental platform with FPGA EP1C12Q240C8 as the controller, the experimental results all support the effectiveness and correctness of the control methods and design methods of APF.