A novel friction model for water-lubricated bearings under boundary lubrication conditions is proposed. The effects of speed, load, surface roughness, and material properties on the friction coefficient are examined. The model is validated through experimental tests using NBR and UHMWPE materials, demonstrating reliability and applicability. The impact of varying speed and load on lubrication states is analyzed, with a focus on the behavior of microconvex contact friction under boundary lubrication conditions. Based on the verified friction model, the influence of surface roughness and texture direction on bearing performance is also explored, offering actionable insights for optimizing bearing design. This model provides critical insights for enhancing friction management and noise reduction in water-lubricated bearings, offering valuable guidance for their design and manufacturing.