Abstract: 1. Total biomass and net production in Rhododendron-Larix,Ledum-Larix and Sphagnum-Ledum-Larix forest types are respectively 285.27ton/ha,196.08ton/ha,and 115.14ton/ha.The biomass of Rhododendron-Larix type has large percentage in storey,but the Ledum-Larix and Sphagnum-Ledum-Larix types have quite large percentage in understorey. 2. The total net production has only a small diference in three types,but the distribution is different obviously within the community. 3. For increasing the biomass and net production,It is necessary to drain the water from forest land,take appropriate cutting system and improve the soil water in forest area of Great Xinganling Mountains.