Although existing models have fully considered the coupling effects of roughness, contact mechanics, and fluid film, there remains a significant gap in the research on the dynamic characteristics of water-lubricated rubber bearings (WLRBs) under mixed lubrication conditions: the critical influence of contact stiffness and contact damping has long been overlooked. To clarify, under mixed lubrication conditions, the interfacial interaction between the rotor and the bearing is primarily dominated by the asperity lateral contact, yet existing theoretical models have not effectively reflected the impact of this mechanism on the dynamic characteristics of WLRBs. To address this, this paper proposes a dynamic characteristic analysis model for WLRBs that considers the asperity lateral contact effect, aiming to overcome the limitations of traditional methods in stiffness and damping calculations. Experimental validation results demonstrate that the developed model exhibits high accuracy with a maximum relative error of 9.15%. The study systematically reveals the influence patterns of key operational/structural parameters—including load, rotational speed, radius clearance, and length-diameter ratio—on the dynamic characteristic parameters of the asperity contact-water film lubrication dual load-carrying zones.