Ultra-high-molecular-weight polyethylene (UHMWPE)/nano silicon carbide (nano-SiC) composites were prepared by compression molding. The effects of a coupling agent and the content of the filler on the filler dispersion and the mechanical and thermal properties of the composites were investigated. The results show that the mechanical properties of the composites first increased and then decreased with increasing SiC content. The macromolecular coupling agent exhibited a much better reinforcing effect than the small-molecule coupling agent. The tensile strength of the composites with 3-aminopropyltriethoxysilane (KH550), -methacryloxypropyltrimethoxysilane (KH570), and silicone powders reached its maximum value when the silicon carbide (SiC) content was 3%. We found that a web of the UHMWPE/SiC/coupling agent was formed and played a significant role in improving the heat resistance of the composites. In addition, appropriate amounts of SiC could increase the crystallinity of UHMWPE via a process of heterogeneous nucleation. The comprehensive performance of the KH550/silicone/SiC/UHMWPE composites was the best. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013