In order to determine reasonable protection measures for the water hammer of accident stopped pumping of water transmission system,according to the engineering characteristics of long-distance and high-lift in pumping station of Xin'an, the paper established water hammer mathematical model of accident stopped pump. It determined the optimal close rule of two stage valve through calcuation, and analyzed the calculation results of stopped pumping water hammer hydraulic transient process were under three different conditions of two stage closing butterfly valve, no shutoff valve and the protection of butterfly valve combined with air valve setted in the outlet of pump. The results showed that the established mathematical model is reasonable and the effect of protection measures of butterfly valve combined with air valve is obvious,witch provide the basis for the design of pipeline and pumping station.