Soil disintegration is one of very important section in soil erosion study and the testing instrument of soil disintegration developed by Jiang Ding-sheng has facilitated and pushed soil erosion study greatly, however, it has some disadvantages, such as unable to reflect the dynamic process of disintegration which leads to lose the optimal observation chance of soil disintegration because it needs time to adjust water level at the beginning of the experiment. Based on the long time researching work of the soil resistance to erosion in Beichuan rupture zone, the method was improved and a new equipment was designed to recognize soil disintegration process. The new method could be widely used to help us to study the disintegration dynamics with higher convenience and efficiency. Moreover, the formulation which demonstrated the amount of the disintegrated soil has a firm physical foundation, and scholars could set up the experiment accuracy by changing balance.