With the rapid development of the city, the scale of urban water supply pipe network is also expanding, and its topological structure is becoming more and more complex, which adds difficulties to water supply security. Among them, the safety of water quality is most urgent. Therefore, a certain number of water quality monitoring points need to be set up in the water supply pipe network. Aiming at optimizing the layout of water quality monitoring sites for water distribution networks, the model was built based on the single node water age method with the effects of other influencing factors on the water quality of the pipeline network taken into consideration and the water supply pipe network of a city in the north as experimental object. By the hydraulic simulation software, the node water age method was optimized, and the optimized layout procedure of water quality monitoring points based on the multi-factor optimization method was designed. The results showed that the location of the water quality monitoring points calculated by the multi-factor water quality monitoring point optimization method based on the hydraulic model is 43.75% coincident with their actual location, not only covering the key water quality monitoring sites of the conventional pipe network in operational water plants and pressurized pump stations but also adding some monitoring points to the water supply demarcation line, pipe network, and pipe network terminal. And the early-warning time for pollution accidents was shorter than that before optimization. In conclusion, using this method to analyze the conditions of the water supply pipe network can provide a better implementation plan for optimizing the layout of the water quality monitoring points.