Abstract: In 2020, a basin-wide flood occurred in the Yangtze River. Benefiting from the innovation and development in hydrological monitoring, forecasting and warning technology system, Bureau of Hydrology(BOH), Changjiang Water Resources Commission made solid technical preparations before flood season and scientifically implemented hydrological forecasting and early warning during flood season, which effectively supported the flood control work. This paper mainly introduces hydrological monitoring innovation technology, such as management service system, technical support system and quality control system of hydrometry, as well as the hydrological and meteorological seamless coupling progressive forecast analysis technology, forecast and operation integration technology. Combined with the monitoring and forecasting and early warning practice in Changjiang River Flood in 2020, achievements and deficiencies in the flood control work were summarized and analyzed. The future development direction and research focus were then proposed in order to improve the ability of hydrological monitoring, forecasting and early warning of the Yangtze River.