Abstract: The measurement of low-velocity and low-flow is a difficult issue in hydrological monitoring. Traditional methods,such as the current-meter method and the float method, do not have sufficient accuracy under low-velocity conditions. With the introduction of new technologies and equipment such as side-scan radar, cableway radar waves, and image velocimetry, the online monitoring capability for high flood discharge at hydrological stations has been greatly improved. However, online discharge monitoring still has shortcomings under conditions of low water levels, low velocities, and small discharges. In response to the development needs of new quality productive forces, this paper takes the Parshall flume at Xiankeng Hydrological Station and the broad-crested weir at Shunfeng Hydrological Station in Jiangxi Province as examples to elaborate in detail on their concrete practices and remarkable results in solving the difficult problem of low-velocity and low-flow monitoring and achieving online discharge monitoring. It also discusses the application of weir-flume flow measurement technology in low-velocity and low-flow measurement and analyzes its potential in online discharge monitoring, thereby providing technical support for the construction of a modern hydrological monitoring system.