Abstract: The applications and the performance test of the slip rings are reviewed. To overcome the diffculties in the measurement of the contact force between the brush wire and the ring in precision satellite slip rings, a measurement scheme based on the cantilever beam theory is proposed and its principle is explained. According to the deformation linearity of the cantilever beam, the unary regression analysis using the least squares method for the measurement data is carried out to obtain the initial loading force. The contact force is finally calculated according to its relationship with the initial loading force.