Under complex and harsh operating conditions, water-lubricated bearings inevitably experience a transition in lubrication state, leading to mixed lubrication regime. The micro-asperities contact occurs on journal-bearing interface. Lubrication, friction and wear characteristics are influenced by surface roughness and elastic deformation. A program to model water-lubricated bearing under mixed lubrication regime was developed. Effects of various working conditions, structural parameters, roughness peaks, and elastic deformation on static and dynamic characteristics were investigated. The influence of four interface conditions on lubrication performance was quantified. The obtained data could guide parameter optimization in subsequent work to mitigate operational risks and prevent adverse impacts, enhancing the reliability and durability of water-lubricated bearings.