Based on static analysis, this paper investigates the effects of interference fit and axial preload on the performance of the low-speed angular contact ball bearing. The results show the bearing with heavy preload and large radial clearance has big contact angle and high axial stiffness. Besides, large interference could result in small contact angle but high axial stiffness. When the bearing has large interference the axial stiffness increases rapidly due to the effect of interference on the axial stiffness stronger than that of contact angle. And the stiffness formula in the paper could provide boundary conditions for the finite element analysis of spindle-bearing system.