Abstract: The single-valued method of stage-discharge relation is an important basis for the innovation and development of hydrological monitoring system in the hydrological field.In this study, the basic principles of this method were systematically elaborated.The development and innovation process of the method in the past 50 years and its practical application in the whole hydrological field were sorted out.Finally, the role of the method in compilation system for hydrological data, hydrometric station network planning, and corresponding flood flow reporting in the future was prospected.The results showed that the single-valued method of stage-discharge relation has promoted the formation of a modern hydrological development model of "combining stationary and tour gauging, prioritizing tour gauging, automatic reporting, and emergency supplementation",and improved the efficiency of the hydrological station single value scheme.The mean flow measurement frequency has decreased by more than 50%～73% compared to previous years.The research results can provide reference for the construction of modern hydrological monitoring system.