Abstract: Profitability in the application of variable nitrogen fertilizer rate technology on rice in Shanghai analyzed by partial budgeting method and investment analyzing method respectively shows that buying expensive combine harvester is not profitable by both methods，but RMB 48228 Yuan of annual profit or RMB 278135 Yuan of return(with 24％ IRR)after 10 years will be gained if renting combine harvester．Because more technical data about production need to be collected，the partial budgeting method is more suitable for the implemented projects while the investment analyzing method is suitable for the projects either implemented or not．Further sensitive analysis and national economic analysis which reflects economic．social and environmental effects can be made with it．