Multi-monomer grafted copolymers, high-density polyethylene-grafted-maleic anhydride-styrene (HDPE-g-(MAH-St)) and polyethylene wax-grafted-maleic anhydride ((PE wax)-g-MAH), were synthesized and applied to prepare high-performance highdensity polyethylene (HDPE)/wood flour (WF) composites. Interfacial synergistic compatibilization was studied via the coordinated blending of high-density polyethylene-grafted-maleic anhydride (MPE-St) and polyethylene wax-grafted-maleic anhydride (MPW) in the high-density polyethylene (HDPE)/wood flour (WF) composites. Scanning electron microscopy (SEM) morphology and threedimensional WF sketch presented that strong interactive interface between HDPE and WF, formed by MPE-St with high graft degree of maleic anhydride (MAH) together with the permeating effect of MPW with a low molecular weight. Experimental results demonstrated that HDPE/WF composites compatibilized by MPE-St/MPW compounds showed significant improvement in mechanical properties, rheological properties, and water resistance than those compatibilized by MPE, MPE-St or MPW separately and the uncompatibilized composites. The mass ratio of MPE-St/MPW for optimizing the HDPE/WF composites was 5:1. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42958.