A method applying 3-D laser scanning to estimate tridimensional green biomass of individual trees was proposed. For each objective tree, some tree parameters were obtained such as height, diameter at breast and crown width of an individual tree from cloud points, which were gotten from 3-D laser scanning. Then, through dividing crown into a plurality of irregular bodies, the volume of crown was regarded as the summation of volume of each body. Finally, the product of tridimensional green biomass and weighted average green looking rate from different perspectives and volume of tree crown was obtained. The method was tested on 13 trees, 6 species, and the results showed that the average tridimensional green biomass of broadleaf trees was 253.02 m3 and 146.75m3 for coniferous trees. It was obvious that the average tridimensional green biomass of broadleaf trees was bigger than coniferous ones, which was contrary to results from traditional method. 