In order to build the first water source with the demonstration effect in Nanjing, the construction project of water conservation engineering in the first-grade protection area of Yangtze River Qiaolin Water Source in Pukou District of Nanjing adheres to the design concept of "minimum intervention" to fully respect the original landform of the beach, and to reconstruct and connect the water system. The water quality is purified through the synergistic action of sedimentation, filtering suspended solids and wetland system. By analyzing the hydrological data, the plants that are resistant to moisture, low maintenance and easy to maintain are selected for water conservation. In combination with the design of inspection access road, the necessary supporting service facilities shall be provided for the first-grade water source protection area. After the implementation of the project, the social, ecological and demonstration benefits are significant, which provides a useful reference for the construction of centralized drinking water sources.