Abstract: This paper analyze the application status of the Geometers Sketchpad in the existing literature in the field of machinery.The formation of four bar mechanism,its evolution mechanism,involute tooth profile,cam mechanism of theanimation,the modeling ideas and key points are carried out by the Geometers Sketchpad.The practice proved that,the modeling process is simple,vivid,intuitive and easy to learn and has highly efficient by the realization of mechanical principle of animation by the Geometers Sketchpad.It provides a new approach to the mechanism principle of animation,and expands the scope of application of the Geometers Sketchpad.