Based on Hertz contact theory, a computational method of contact deformation in operating process of ball screws is established in terms of variable contact angles and the centrifugal force. Through the force balance equations, contact deformation in operating process is derived. Taking a ball screw as an example, the influence of its operating condition, contact angles and helix angle on contact characteristics is studied by numerical method. Analysis indicates that the contact deformation on the side of screw decreases and that of nut increases when the screw rotation speed increases and there exists a speed that the later is greater than the former. At the same time, the difference between contact angles increases. Variety of contact angles increase as the axial load decreases, which leads to higher influence on contact deformations. Contact deformations decrease as the contact angle and helix angle increase.