Abstract: The crown breadth, plant height and leaf biomass of 44 plants of Buxus microphylla were measured in the test. 34 plants were used to establish the model among them. The binary regression analysis of leaf biomass was made by using Excel 2003 to establish the estimate formula of leaf biomass of B. microphylla. And other nine plants were used to validate the model. The results showed that the leaf biomass of B. microphylla had no significant correlation with the plant height（P0.05）. The leaf biomass showed a significant correlation with the crown breadth（P0.05）. The estimation formula of leaf biomass of B. microphylla was as follows： Y（g, leaf biomass）=156.12＋7.332X（cm, crown breadth,P0.05）.