Basalt residual soil shows significant disintegration owing to climatic influence. Most existing studies on disintegration of earth materials focus on rocks, with minimal attention given to soils, and do not consider climatic impact. To investigate the effects of disintegration on residual soils derived from basalt, samples from Leizhou Peninsula, China, were first subjected to wetting–drying cycles, used for disintegration test in air, and then soaked to assess the effect of the dry and wet seasons that occur in the area. The results showed that repeated wet–dry cycles reduced the bonding within and between the soil aggregations. The majority of disintegrated material in the air transformed from coarse particles to fine particles, which may lead to severe disintegration, and disintegrated material in water showed a transition from a lump or fragment eventually to mud. Furthermore, compared with sesquioxides, other chemical components and minerals in soils had a less prominent function in disintegration, which significantly deviated from that of rocks containing expansive minerals. Aggravation of disintegration by climatic influences was evident in the structural degradation. Based on these results, we have interpreted the disintegration mechanism of the residual soil.