The power grid harmonics and the reactive power compensation technology are the main technologies in the power system, and it"s a technology that requires a lot of consideration when the new energy power electronics is highly permeable. It is mainly aim at that problem of harmonic management and reactive power compensation, a kind of invert based on the cascade H-bridge structure, which can realize the control of the harmonic and reactive power compensation, can realize the control of the reactive current, can also produce the target sub-harmonic, and the result is matched with the set value or theoretical value by PSCAD/EMTDC simulation, and the simulation research work proves the feasibility of the test system in theory.