The control arms, as an important part of automobile components, are widely used in auto assemblies. The ball joint sealing of control arms is a key process to chassises assembly and the sealing quality directly determines the lifespan of steering systems of automobiles. In this paper, based on the aluminum control arms, a precise control system of revolving-riveting equipment spindle displacement was developed and the effect of riveting equipment spindle displacement on torque of ball joint sealing was studied through experiments method. The results showed that the torque of ball joint is directly related to the displacement of spindle, and a better sealing quality can be achieved when the displacement of spindle was in a reasonable range. The research will provide elementary technical support to the ball joint sealing of automobile control arms.