Abstract:in this article, the author have made a study on the productivity of chinese fir plantation's ecosystem which located at the north mariginal of central subtropics, he alse established two type relative telationship between leaf area & biomass and between leaf amount & stemwood's biomass,had compared the annualnet increment and leaf's net phtosynthesis efficiency among different growth class's forest trees; The resultcan provide a theoretical foundation for chinese fir plantation's fast gowth and high yield.