Being capable of predicting the friction torque of the ball screw accurately allows the designer to correctly determine the energy loss and heat generation rate. Based on the theory of creep, the sliding forces between the ball and and nut raceway were calculated, then a creepage analytical model for the ball screw was established. This model was used to analyze the quantitative relationship between the creepage/spin and the tangential tractions. The result shows that there exists non-linear incremental relationship between creep rate and friction, and the spinning motion will cause an additional traction transverse to the rolling direction. Tangential movement and the spin motion have a strong coupling effect. Finally, the ball screw tests were performed on a special machine, it was found that the predictions of the new analytic torque model are in good agreement with the test results.