The damage probability and the leakage level of pipelines in different earthquake intensity were calculated according to earthquake damage evaluation model and probability theory for the reason of studying the leakage and hydraulic characteristics of water supply network in ground motion. The reduction coefficient was introduced to improve the seismic reliability analysis of the pipe section, by means of comparing with the traditional calculation method, the rationality was verified. Monte Carlo simulation technology application in the service of water supply network was developed, with considering leakage and burst of pipes as well as compiling the program, the earthquake leakage of a large-scale water supply pipeline network had been calculated. The result is consistent with those of the actual earthquake disasters and provides an effective means for evaluating the failure state of the seismic function of the water supply pipeline network.