Abstract: A greenhouse tomato dynamic model is developed that the solar radiation is taken as the basic driving factor，and a computer simulation system is programmed on MS Windows 98 also．The model as a multi-functional perfect one includes the most important mod ules such as solar radiation，carbon balance analysis，crop morphological development，dry matter partitioning，etc．The computer simulation system is designed with mixed languages by PowerStation Fortran 4．0 and MS Visual Basic 6．0．By using this programming technique，the software keeps friendly and harmonious in function and interfaca．