For plain pad bearings,the thermal hydrodynamic lubrication model was built by considering the variations in oil density and viscosity with temperature rise.The temperature field was solved by finite differential method,and the pressure field by multi grid method.Based on several cases of surface temperature boundary conditions the influences of central dimples on the load carrying capacity were discussed.Furthermore,the influences of dimple size were analyzed.Results show that the contribution of central dimple may be positive or negative,depending on not only size dimension but also surface temperature.Especially it is found that when thermal wedge plays dominant role at the surface temperature boundary condition that stationary surface remains constant temperature yet moving surface is adiabatic,the load capacity is reduced by central dimples,implying that it is impracticable to improve the load capacity with surface dimple texture under such conditions.