Abstract: A project of computer-aided design is presented for ball-inspection’s controlling surface,which can control ball’s rotation by means of swing of rotation axis in order a laser beam to be able to scan the whole sphere.With coordinates on the sphere,a precise expression for the controlling surface is built,which avoids the shortage of the existing ones that the required precision can be reached only while the rotation axis swings slightly.After the relation between variables in the coordinates is established,the accurate mathematical model for the ball rotation is built,and computer simulating proves the model’s correctness.