Abstract: The review, summary, and analysis of meteorological services for heavy rainfall and flood disaster play an important role in emergency disaster mitigation. Taking the extreme heavy rainfall event in Beijing from July 29 to August 2, 2023 as an example, Beijing Meteorological Observatory carried out progressive meteorological services known as "31631" in accordance with the key time nodes of major disastrous weather prevention, namely "before the disaster, on the brink of the disaster, during the disaster, and after the disaster", and established a progressive forecasting and warning mechanism for disastrous weather. Facing this rare extreme heavy rainfall event, Beijing Meteorological Service fully exerted its role as the "starting pistol" and "message tree" in the municipal flood control and emergency response system. It made accurate predictions and timely warnings, thus gaining a precious time window for coping with the heavy rainfall. The advance and efficient progressive forecasting and warning services have greatly improved the response efficiency between meteorological services and other departments, and have made the first line of defense for disaster prevention and mitigation more solid.