Zeolitic imidazolate frameworks (denoted as ZIF8) were combined with carbon nano-fiber (denoted as CNF) by a facile liquid-phase chemical route to afford ZIF8-CNF nano-hybrid as the filler of ultra-high-molecular-weight-polyethylene (abridged as UHMWPE). The as-prepared ZIF8-CNF nano-filler was incorporated into UHMWPE matrix via hot pressing to obtain the UHMWPE-matrix composite. The effects of CNF, ZIF8, and ZIF8-CNF on the thermal stability, mechanical properties, and fretting wear behavior of UHMWPE were comparatively investigated based on thermogravimetric analysis-differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, and stress-strain testing. Findings indicate that ZIF8-CNF can significantly promote the crystallization of UHMWPE and improve its thermal stability and mechanical properties. Besides, the high interfacial strength between the ZIF8-CNF nano-filler and UHMWPE matrix is favorable for facilitating the transfer of load from the polymer matrix to the inorganic filler and for the formation of transfer film on worn steel surface, thereby alleviating adhesion, abrasion, and plastic deformation. Therefore, the ZIF8-CNF/UHMWPE composite exhibits much better fretting wear resistance than neat UHMWPE, CNF/UHMWPE composite, and ZIF8/UHMWPE composite.