Abstract:ased on some of the best models over the world, after several years‘ simulation experimentation and research, a maize (Zea mays L.) physiological-ecological simulation model (MPESM) was built successfully. MPESM consists of five submodels: viz. generation of meteorological data, water effects, nitrogen effects, maize development, and maize growth. Each submodel consists of some specific mathematic models. MPESM is a computerized simulation model bearing five main functions: (1) simulation on the effects of environment (meteorologial factors, soil moisture and nitrogen supply) on maize growth and development; (2) simulation of maize development; (3) simulation of maize growth; (4) simulation of yield formation; (5) decision of optimum maize cultivation management. The major structure, hypothesis, handing procedures and mathematic equations of MPESM are described here. The simulation of soil moisture, nitrogen assimilation, the development, growth and yield of maize were verified to be effective in terms of many years‘ experimental data.