三悬摆仪是测量固体转动惯量的一种常用仪器.由于结构简单,操作方便,又能达到一定精度,所以在力学实验中,受到普遍重视和欢迎.但是,我们在使用这种仪器过程中,发现它在结构上尚有一些缺欠,给调整工作带来困难,常常使测量结果出现较大误差.为此,我们对原来的仪器进行了一些改造,并取得了较理想的结果. Three pendulum instruments are commonly used instruments for measuring the inertia of solids. Due to their simple structure, easy operation, and ability to achieve certain precision, they are widely appreciated and welcomed in mechanical experiments. However, we use this instrument in the process. It is found that it still has some deficiencies in its structure, which brings difficulties to the adjustment work and often results in relatively large errors in the measurement results. For this reason, we have made some modifications to the original instrument and achieved satisfactory results.