Abstract: In order to realize precise management and provide advice for tomato production. A tomato long season production expert system software was designed which adopted Visual Basic 6.0 and Windows programming measure language of process based on data of tomato long season cultivation technique.The system may be used to prevent disease and pest according to the parameter of environment in greenhouse. By calculating effective accumulative temperatures of tomato, the harvest data and yield of tomato fruits can be deduced and forecasted in the expert system, so the system will have good foreground for extending tomato long season high yield cultivation technique in greenhouse.