Comprehensive weather forecasting expert system which centres in "Intelligent Database" is a common expert system shell and an operational process. Compiled mainly using computer languages such as Turbo-C,Turbo-prolog and Basic etc. ,this system consists of six major parts:objective analysis and system distinguish,intelligent database including real time and history,analogous process prediction based on the moving evolution of major weather system,physical element diagnosis,experience forecasting and comprehensive decision. Every part is relatively independent but all parts can be combined executing together. As an applied advanced technology, the system has a complete function and a rational structure design.