Fine root distribution and biomass were examined in 2005 using auger/soil core method in five forest communities along the northern slope of Changbai Mountain. Selected forest communities are Broad-leaved Korean Pine forest, Asian white birch forest, David poplar forest, Spruce-fir forest and Ermans Birch forest and belong to different vegetation belts of different altitudes. The results show that fine root biomass and seasonal dynamics vary among different forest communities. Asian white birch forest has the highest monthly mean biomass (5.1340 t/hm^２), followed by Spruce-fir forest (5.0530 t/hm^２), Ermans Birch forest (4.9255 t/hm^２), Broad-leaved Korean Pine forest (4.4919 t/hm^２) and David poplar forest (3.9372 t/hm^２). The difference between highest and lowest monthly mean values is about 72% in Broad-leaved Korean Pine forest, 73% in Asian white birch forest, 26% in David poplar forest, 56% in Spruce-fir forest, and 144% in Ermans Birch forest. Along growing season, fine root growth is generally at the highest level in spring in all forest communities and reaches another peak in the early fall (September) in some communities. Fine root mortality usually follows new root growth and total biomass of dead fine roots reaches its maximum level at the end of growth season. Over 72.9% of fine roots are distributed within 0～10 cm of soil surface, which varies slightly among different communities. The fine root biomass in top 10 cm of forest soil surface follows the sequence of Asian white birch forest, Broad-leaved Korean Pine forest, Spruce-fir forest, Ermans Birch forest and David poplar forest from high to low