Abstract: The paper describes the construction and operation of groundwater monitoring network on the Changjiang Three-Gorges Reservoir induced earthquakes and the result of tentative operation and examination. Moreover, the inner quality of monitoring data are analyzed and evaluated. The results show that the data from the network are of relatively high inner quality. They can be used to provide not only groundwater precursor for predication of the trend of reservoir-induced seismicity above a certain magnitude, but also the valuable data and reference for further study of reservoir-induced earthquakes.