The focus of national severe weather forecasting is transforming from shortrange forecast to the pattern of the coexistence of shortrange forecasts and shorttime forecasts. For the requirements of severe weather forecast techniques and service, this paper presents the development of national severe weather integrated platform. Based on the core requirements of meteorological data organization and plotting, the development of data analysis system, meteorological autoplot system and WEB search and display system are developed. The data analysis system, as the core of the whole platform, integrates various data, including mutisource monitoring data and mesoscale NWP model forecast and global NWP model forecast, and develops the dataprocessing technology for severe weather monitoring and nowcasting, shortrange forecast and shorttime forecast. The key technology includes: starting from considering the unstable energy, water vapor, uplift, and vertical wind shear, the classified shortrange analysis and prediction technology summarizes conceptual models for different types of severe weather. The severe weather tendency forecast part guided by the severe weather condition analysis, generates a classified severe weather forecasting model and products. The shortterm forecast test part integrates the applications of mososcale NWP, ensemble prediction, mesoanalyses and sounding analysis, and highlightes the seamless link between the observation in the past 3 h and the prediction of the future 12 h. Based on the existing convective system monitoring technologies, the autoalarm products of radar features, severe weather events, convective indices and alarm signals are developed to improve the convective weather monitoring and nowcasting technology. Meteorological autoplot system includes the functions of data analysis, automatically plotting, etc. In the term of service, the WebGis tech is applied to share the national products to the countylevel weather stations and vice versa.