Decision support system is a new computer application field. It is developed up in the middle of 80s. C.T. Kitzmiller et al. firstly put forward the couple system in industry circle and integrated symbolic with numerical computing in expert System. In recent year, the couple system that made up of two technique is gradually accepted by researcher who working at agricultural expert system and called agricultural decision support system or expert system based on model. At present the most successful one is GOSSYM/COMAX system based on cotton simulation model. It has improved the performance and practicality of GOSSYM greatly. The MOCMDSS that developed by professor Liu Keli etc. (Inner Mongolia Agriculture University) is the expert system based on model on the basis of combinative experiment sited different place in many years. The system can provide comprehensive, precise, Fast guidance for maize high-yield and high-efficient cultivation management in main growing region, Furthermore, the economic benefit is prominent, It has the strong character of science, application, practical and universal. It is easy to transplant and expand. Therefore, it has brilliant application prospect for improving the level of maize management and production in our country.