The geometrical and mathematical model of angular contact ball bearing are established. A thermal elastohydrodynamic lubrication full numerical solution is carried out when the inner ring and rolling sphere are made from Si3N4 and GCr15 after considering the lubrication performance of several different bearing steels. On the basis of it，the effect of angular contact ball bearings’ several essential parameters (marginal adaptation、number of steel ball etc) and variation of contact angular with axial force on lubrication performance are considered. After the thermal elastohydrodynamic lubrication analysis of angular contact ball bearing under pure axial force，the pressure、film thickness and temperature distribution under different axial force are acquired. Results show that minimum film thickness is thicker when the inner ring and rolling sphere are made from Si3N4 and GCr15, but the later temperature is lower. The larger of the alignment, the thicker of the lubrication film thickness. The whole pressure is lower, film thickness is larger and the temperature of rolling sphere is lower with the increasing of rolling balls. The actual working contact angular is increased with the axial force increasing. The changing of contact angular makes great influence on elastohydrodynamic lubrication, minimum film thickness increases and maximum pressure are lower after considering the changing of contact angular with the variation of axial force.