Ultra-high molecular weight polyethylene (UHMWPE) fiber is considered as one of the high-performancefibers. However, the inert surface of UHMWPE fiber limits its application in many fields. In order to optimizethe application of UHMWPE fibers in functional and composite fields, this work introduced a specialsurface structure of the UHMWPE fibers. The designed surface was formed by the flower-shaped ZnO (FZnO)crystals, which endowed the UHMWPE fibers with photocatalytic property. Moreover, F-ZnO on theUHMWPE fiber surface enhanced the roughness of the fiber, which improves the interfacial bondingstrength of fiber-reinforced composites. The experimental results showed that the surface wettabilityof the F-ZnO-UHMWPE fibers was improved significantly. Moreover, F-ZnO-UHMWPE fibers were usedas immobilized photocatalyst, and the degradation rate of rodamine B reached 53.3 %. F-ZnOUHMWPEfiber also could be used in fiber-reinforced composites fields. Compared with the pure rigidpolyurethane (RPU) and UHMWPE fibers/RPU composites, the tensile strengths of F-ZnO-UHMWPEfibers/RPU composites were improved by 130.3 % and 44.2 % respectively.