AbstractThree layers of wood-based composites of planed lumber-UHMWPE-veneer structure were prepared using polyurethane (PUR) as the resin matrix. The effects of ultrahigh molecular weight polyethylene (UHMWPE) fiber on the wood’s bending performance, tensile properties, and other mechanical properties, such as shear resistance to the agglutination interface, were investigated. Chemical constituents of debonded fibers were characterized by infrared spectroscopy (FTIR). The results show that PUR could feasibly be used to manufacture UHMWPE fiber/wood composites. UHMWPE fiber played an important role in the wood destruction process and improved the flexural performance of the lumber. This positive effect was closely related to the thickness of veneer. When fiber was within the load-bearing strength range, there was a positive correlation between the tensile strength and the bonding distance. Meanwhile, the reinforcing effect of UHMWPE fiber strongly affects the performance of the bonding interface under shear.