A contact analysis of rollerraceway under the combined load was carried out based on Hertz contact theory,and a lubrication state analysis model of wind power main bearing was established based on EHL theory.With a type of MW scale wind power main bearing as the example and based on this model,the contact load and contact pressure distribution between roller and rollaway under limited conditions,the contact load and contact pressure distribution along the roller isoline of the maximum loading roller,as well as the mean speed on the contact area of roller and rollaway were researched,and the main bearing lubrication condition under extreme load was analyzed.Results show that the oil film is thin in both ends and thick in the middle along the roller isoline due to the stress concentration of roller ends.The oil film thickness along the roller isoline of rollerraceway and the contact surface roughness of roller and rollaway is in the same order of magnitude,so the surface roughness of roller and rollaway has an important influence on the lubrication state.The lubrication condition of the main bearing can be improved by modifying the bearing structure,the lubrication parameters and the machining quality.