Abstract:High frequency and high quality flood data of rivers,lakes, and reservoirs, and professional hydrological analyses results can provide support for scientific decision-making of flood and drought disaster prevention.According to the current situation of flood analysis of rivers,lakes and reservoirs,an overall design concept of online flood analysis service platform is proposed by taking hydrology in Zhejiang Province as an example, which is mainly composed of basic support system, online processing system, business analyzing system,and service sharing system.Consequently,development achievements,which contain stable and reliable flood monitoring nets, high quality and high efficiency flood data, professional and authoritative flood analysis, socialized flood information service, and inter-department sharing, can be reached. Furthermore, the digital transformation and development of flood and drought disaster prevention can be promoted.