Self-lubricating spherical plain bearings pad force of the state directly affect the contact performance, thus affects the service life. Therefore, based on the self-lubricating spherical plain bearing GE30 C, the finite element model（FEM） is established without changing the assembly size and axial swing angle. The evaluation index of the performance is determined and orthogonal test is carried out. The results were analyzed by comprehensive scoring method and range analysis method to obtain the characteristics of the major structural dimensions on the contact properties. The optimal size is determined and the contact performance.is improved. The results show that FEM can study the contact performance of the bearing and broaden the research method of the performance.