In order to reduce the manufacturer cost, 5 and 7 times harmonic passive filter and active filter are in parallel in this structure; while 11 series resonance branch shares part of the voltage of active filter. At the same time series with the fundamental resonance branch makes the fundamental voltage on the resonance branch and decrease fundamental frequency current of the active filte. A double closed-loop decoupling control method is adopted and the Matlab simulation analysis is performed, which verifies that the active filter can effectively suppress the harmonic in power grid .