Investigation of wood plastic composite(WPC) based on crosslinked polypropylene(X-PP)/wood flour was explored. The peroxide/silane was used as crosslinking system. The sauna incubation under moisture saturated oven was applied to accelerate the competition of the siloxy/moisture networking reaction. There were three parts of the research work; design of experiment, toughening of WPC and the effect of peroxide, silane and PP copolymer on properties of the WPC, respectively. In this published work was focused on the toughness improvement of the composite. Ultra-high molecular weight polyethylene (UHMWPE) and Ethylene propylene diene terpolymer (EPDM) were employ to improve impact strength via blend matrix. Composites were compounded into pellets by co-rotation twin screw extruder and test specimens were prepared by injection molding. Sauna incubation at 105oC for 12 hrs in oven chamber was performed to accelerate the final silane condensation crosslink reaction. Impact strength, flexural properties and heat deflection temperature testing were conducted. Impact strength, HDT and flexural modulus can be improve with increasing UHMWPE content, and achieved optimal values at 5-10 phr of UHMWPE. Adding an EPDM elastomer to the matrix blends, reduced flexural strength and modulus but increased impact strength. When incorporation of EPDM into the PP/UHMWPE blends was exhibited much higher impact strength than that of the PP/UHMWPE binary blends. Silane crosslinked by sauna treatment can improve the impact strength, HDT were also much higher for the crosslinked composite compared to the non-crosslinked.