Abstract: The dam seepage flow directly reflects the safety condition in the dam structure, so the accuracy, long-term stability and reliability of seepage monitoring data are very important for dam safety. According to the problems in the application of the low-flow seepage meter developed in the earlier period of the investigation and research, the optimal design is carried out. The separation of measurement and drainage is realized by the design of the rotating measuring vessel, which not only simplifies the structure of the instrument and reduces the cost of the instrument, but also solves such problems as unreliable volumetric methods under the influence of water erosion and seepage. By adding the design of wave-proof pipes and spillway boards, and optimizing the design of liquid level switches, the measuring precision of the instrument is improved, and the more accurate data basis is provided for dam seepage monitoring, the problem that the instrument cannot continue to measure after recharging increases the reliability of the instrument and has wider adaptability. The device adopts zero-valve design, which solves the problem that the valve is jammed or cannot be completely closed due to the silt entering the valve, and the measurement is abnormal or cannot be measured, and improves the long-term stability and poor reliability of the instrument, the self-cleaning device is increased, the maintenance workload of the instrument is reduced, and the adaptability of the instrument is enhanced. Through a performance test in the factory and practical application in four hydropower stations, it is proved that the optimized instrument has advantages like high measuring precision, good reliability and long-term stability, simple structure and convenient field installation, and provides reliable guarantee for dam seepage monitoring.