Abstract: Alkali substances, such as cement and lime, have been largely used to reinforce soil structure. But the laterite has been chronically eroded by alkali materials. Based on the chemical analysis of mutual deterioration of the materials, accelerated life dip in calcium hydroxide is designed for the laterite. The hydraulic factors are compared and the ion concentrations of seepage are tested. The test results show that the alkali substances reduce the cohesion of sesquioxides, depletes the clay particles of the laterite, and leads to poor-gradation of soil. Mutual deterioration of alkali reinforcement materials and acidic laterite is released. The leakage mechanism of contact zone is found for the acid and alkali materials. It is helpful for the strengthening of laterite dams.