Abstract: A project of computer-aided design was presented for ball-inspection’s controlling surface,which could control ball’s rotation in order that a laser beam could scan the whole sphere.The motion pattern of a scanning point was studied in case a fixed laser beam was pointing at a rotating ball with fixed center. A mathematical model of the scanning point and the angle-velocity vector was built up with differential equations for the motion manner.With this model,a controlling surface was designed to control the ball’s rotation.The mathematical model and the controlling surface were successfully simulated with Simulink and OpenGL respectively.