The majority of underground cemented soil projects contact with underground corrosive medium environment directly, which will lead to the deterioration of cemented soil material gradually or even failure. The discharged polluted water from the open channel near construction site is used as a kind of corrosive medium to produce test pieces of cemented soil with different cement content. In both polluted water environment and clean water environment, the compressive strength and shear strength of cemented soil with different cement content and different ages are compared. The results show that when the age is 30 days, compressive strength of cemented soil with the same cement content is almost the same in polluted water environment and clean water environment. Compressive strength of cemented soil gradually increases with the increase of the age. However, the increase extent of compressive strength in polluted water environment is significantly less than that in clean water environment. After 90 days, compressive strength of cemented soil no longer increases in clean water environment, and compressive strength begins to decrease in polluted water environment. The internal friction angle and the cohesion of cemented soil gradually increase with the increase of the age and cement content in polluted water environment and clean water environment. The internal friction angle and the cohesion begin to decrease in polluted water environment after 90 days.