An improved algorithm, dynamic collision detection with optimum discrete interval is presented to improve the efficiency of dynamic collision detection. The algorithm based on the minimum distance between two objects with relative movement to determine the next discrete position, on which collision or interference is free. The method using the minimum distance as discrete interval to determine the next interference-free position makes each interval longest under the constraint of safety so that the reliability between the moving object-pair is ensured while the efficiency is improved. The practical demonstration has proved that the improved algorithm is capable of high performance than that of the collision detection method with even discrete interval. This algorithm has been successfully used in a verification system of inspection process by secondary development of Pro/Engineer.