The characteristics of benefit assessment of major meteorological disaster service are analyzed. The benefit assessment models, indexes, and working flow are constructed, and a comprehensive assessment is conducted in aspects of weather forecast accuracy, forecasting service coverage, feedback from government decisionmaking departments, and overall assessment of service benefits, and so on. The system is based on the Asp.Net platform and B/S (Browser/Server) structure of. Taking the low temperature and snow/freeze disaster of 2008 as an example, an operation application assessment is carried out with the system, which proved a useful tool for evaluating the benefits of major meteorological disaster service.