Abstract: Spraying Polyurea technology is a new solventless, pollution-free green construction technology. In order to meet special requirement of the watertight roof for the workshops at hydraulic power stations, spraying Polyurea technology was adopted in the anti-seepage treatment. It showed that this technology was of the advantages such as convenience, good flexibility, high strength and durability, worthy popularization in roof waterproof treatment projects at hydropower stations.