现有的拉脱法测量液体表面张力系数的实验中存在人为选取液膜拉断点等影响测量结果的弊端. 本文利用PASCO实验平台搭建了一套能够实现高频率拉力测量及采集的实验装置. 利用该实验装置，首先系统地测量了金属环所受拉力，然后分析了金属环出水过程中界面张力、浮力的变化，再现了这一过程的物理图像. 对测量得到的数据进行拟合，得到了水在空气中的表面张力系数值为0.0705 N /m，与表面张力系数标准值相差2.7%.

Currently，in the experiment of measuring the surface tension coefficient of liquid with pull-off method， when the liquid film breaks，the judge of the moment could cause artificial error. In this paper，a set of experimental equipment which can measure the tension in high frequency is built by using the PASCO experimental platform. With this equipment，the tension acting on the metal ring is measured systematically. The process of the metal ring getting out of water is studied. The change of the interracial tension and the buoyancy in this process are also analyzed. The surface tension coefficient of water in air is extract through fitting the data measured. The coefficient achieved in this paper is 0.0705 N /m which had about 2.7% difference from the standard value.