This experiment aims at researching the change regulation of soil stability under the condition of dry-wet cycles of all layers of soil in collapsing gully erosion area where granite develops. By conducting the experiment of dry-wet cycles for typical development of all layers of the soil (eluvial horizon, illuvial horizon, cambic horizon and parent material horizon) of granite slope in collapsing gully erosion area in Tongcheng, Hubei province, we analyzed the influence of the times of dry-wet alternations on the development of soil cracks, the disintegration characteristics of soil and the shear strength of soil of all soil layers. The results showed that: under the influence of dry-wet cycles, the soil developed cracks gradually; after the second cycle, main cracks arised, and the crack ratio increased significantly; after that, cycles developed small cracks. After 4 times of dry-wet alternations, the size of the crack ratio of the 4 layers of soil listed as illuvial horizon＞eluvial horizon＞cambic horizon＞parent material horizon. With the increasing times of dry-wet cycles, soil cracks developed, soil disintegration characteristics of all layers of soil increased constantly, and the disintegration of eluvial horizon and illuvial horizon was slow, while cambic horizon and parent material horizon could completely collapse in a very short time; With the increasing times of dry-wet cycles, the shear strength of soil attenuated constantly, and the amplitude attenuation of eluvial horizon and illuvial horizon decreased, while the amplitude attenuation of cambic horizon and parent material horizon increased.