Aiming　at　the　problems　that　traditional　PI　control　of　DC　capacitor　voltage　has　Udc　slow　dynamic　response,　the　period　averaging　dynamic　model　of　APF　including　Vdc　is　established　based　on　KVL.　In　order　to　have　a　good　linearization　control　effect,　the　inverse　control　strategies　is　presented　for　three-phase　four-leg　Active　Power　Filter,　and　Aiming　at　the　problem　that　the　APF＇s　dynamic　model　is　a　multi　-variable,　nonlinear　and　strong　coupling　system,　the　diagonal-matrix　decoupling　method　is　adopted　in　this　paper　and　the　coupling　system　is　decoupled　into　three　indepent　firstorder　linear　subsystem:　reactive　current　iq,　zero　sequence　current　iO　and　DC　capacitor　voltage　Vdc.　The　simulation　results　show　that　a　rapid　transient　response　can　be　obtained　under　the　inverse　control　method.