Abstract: As the pressure control equation (i, e. Reynold's Equation) was transformed into Poisson's Equation in this paper, the pressure distribution is solved using Boundary Element Method. The step numbers of algebraic equation group are effectively dropped, the calculation time of computer is largely decreased and the precision of calculation result is raised. Because spiral groove bearings are of higher load-carrying capacity and less friction force in comparison with the other bearings under high speed condition, they are widely used in high speed rotating machinery. Therefore, a spiral groove thrust bearing of varying depth is choosed as an example of the application of Boundary Element Method in the paper. The treatment of boundary condition is introduced and the influence of dimensional parameters on bearing's performance, such as load-carrying capacity, flow rate and frictional torque are discussed. Also, satisfactory results are presented.