Abstract: In the current college physics experiment teaching，the experiment of measuring objects’processional moment by torsion pendulum method has some logical confusion because of the intertwining with the geometric method. This paper proposes that the definition method rather than the geometric method is directly used to calculate the torsion coefficient K. Then，this paper rearranges the experimental content and makes the process more clearly.

Key words: college physics experiment, processional moment, torsion pendulum method