Abstract: In recent years, Web-based meteorological application platform plays a key role in meteorological data sharing, weather forecast cooperation and early-warning, weather service and meteorological decision-making application. Many meteorological Web service systems are developed based on flash plugins or commercial software such as ArcGIS. For instance, French Meteorological Department develops Synergie-Next, German Meteorological Department develops NINJO, and ECMWF develops MetView adopting WebGIS to integrate the WMS and WMF map services. However, there are still some limitations, for example, these applications cover only limited kinds of meteorological data, and it is expensive and inconvenient to develop WebGIS applications based on third-part plugins or commercial GIS software. Besides, some systems are platform-dependent and not robust when run on different operation systems. Finally, some Web-based applications don't support meteorological data analysis and interoperation well.To solve these problems, MICAPS4 Web Platform is developed by National Meteorological Center(NMC) using JAVA and the Brower/Server mode, and it integrates various models including the VECTOR Model, RASTORV Model, GIRD Model, which can store, process different kinds of meteorological data efficiently. It can be used to publish kinds of heterogeneous meteorological data sources through Web efficiently, and with the help of integrated analysis algorithms and models, this platform could be used for developers to develop kinds of meteorological applications systems. Meanwhile, some modern key technologies are used in this platform, such as drawing based on HTML5, and meteorological data real-time distributed process computation with STORM. MICAPS4 Web Platform provides efficient and common server-side and browser-side interface API, making it a convenient meteorological Web platform which could be used by developers at different levels of meteorological departments.MICAPS4 Web Platform and other applications developed by national or some provincial meteorological observatories with its SDK run stably in real-time weather operation, which illustrates strong practicability and expansibility in massive data Web publishing, Web client rendering, forecast analysis and interoperation, and data monitoring. MICAPS4 Web Platform provides efficient server-side and browser-side SDK API, through which national developers already develop kinds of metrological forecasting and early-warning information platforms, and meanwhile, local developers can also develop local meteorological Web information platforms quickly. There are still some problems to be solved further, such as researches about micro-services and simplifying these SDK APIs.