This paper designs an environmental parameters prediction system based on web for greenhouse. The system is designed using the MVC framework, and includes monitoring module and prediction module. The system can obtain the main environmental parameters from sensors, such as light, temperature, humidity, CO2 and so on. Based on mass and energy balance principle, the prediction module of the system can predict the parameters of the greenhouse environment each day. The system displays the measured real-time data and the predicted data for the users to manage greenhouse easily. This paper provides a specific method to realize an intelligent management system for greenhouse.