Abstract:By study on a lot of sample plots and individual trees of Pinus Massoniana,it is proved that there is a close relationship between the biomass and the volume,so that the biomass of stem，branch，leaf，and root can be estimated very well respectively by the use of diameter at breast height and tree height．The single-tree biomass growth can be precisely predicted by the Richards model．The stand biomass change can be regulated by mean stand diameter，stand height and stand density，while the undergrowth biomass can be controlled by the cover-degree according to stand types．