Abstract: In order to study the thrust bearing system of Three Gorge hydroelectric generating set, the mathematical model of preselecting the pad face shape is constructed. The influence of the pad face shapes on the maximum oil film temperature, maximum oil film pressure, and minimum oil film thickness of the bearings was analyzed, by combining the established mathematical model and the software specifically developed for the analysis of three dimensional thermohydro dynamic lubrication, with six kinds of pad face shape including plane shape, cylinder shape, saddle shape, transverse bend shape,spherical shape, and anti transverse bend shape as the targeted research objects. As the results, the pad shapes characterized by circumferential convex and radial hollow are of advantages to form oil wedge and hence greatly improve the lubrication performance of the bearings.