Marine water-lubricated stern bearings usually suffer severe abrasion and poor lubrication under the conditions of low-speed and heavy-load. A large number of studies have demonstrated that the addition of microcapsules and modified lubricants can improve the lubricating properties of the materials at the expense of mechanical properties. In order to simultaneously improve the combination property of bearing material, the current study investigates the effect of aramid fiber modification and its addition on ultra-high molecular weight polyethylene (UHMWPE) properties. The results revealed that the addition of aramid fibers into UHMWPE could improve the ultimate tensile strength and shore hardness of the composites; however, the tribological properties are not significantly altered. The synergistic modification effect of microcapsules and aramid fibers leads to an optimal combination of tribological and mechanical properties. Overall, the current work presents a novel strategy for the design of water-lubricated bearing materials for low-speed and heavy load conditions.