An interface engineering strategy is employed to reduce charge recombination in inverted polymer solar cells by simply modifying active layer with an electrolyte PEDOT:PSS solvent between photon-active layer and MoO3 hole transfer layer. The incorporated PEDOT:PSS electrolyte can improve interfacial contact between PTB7:PC71BM and electrode via establishing a composite PEDOT:PSS/MoO3 hole transfer layer. The composite interface layer can optimize boundary topography and adjust the anode energy levels alignment, leading to a uniform and ordered hole transmission channel. The tailored boundary morphology eliminates the defect states and interfacial barrier, resulting in the simultaneously enhanced short-circuit current, open-circuit voltage, and fill factor (FF). These results demonstrate that PEDOT:PSS/MoO3 composite layer owns a versatile potential using in high-performance organic photovoltaic devices.