Abstract: The storages of biomass carbon under cropland,rangeland,natural secondary forests(brushwood,natural secondary forest dominated by Quercus liaotungensis or Populus davidiana) and the plantation of Larix principis-rupprechtil(13,18 and 25-year-old) were investigated.It was found that the above-ground biomass carbon for natural secondary forest,plantation of larch,cropland and rangeland was 14.93～25.92 t·hm-2,11.97～45.39 t·hm-2,0.83 t·hm-2,0.49 t·hm-2,respectively.The storage of underground biomass carbon for the natural secondary forest,the plantation of larch,cropland and rangeland was 6.50～7.55 t·hm-2,6.48～7.64 t·hm-2,1.09 t·hm-2,1.61 t·hm-2,respectively.The above-ground NPP carbon for the natural secondary forest,the plantation of larch,cropland and rangeland was 2.97～5.15 t·hm-2·a-1,5.07～6.49 t·hm2·a-1,0.83 t·hm-2·a-1,1.09 t·hm-1·a-1,respectively.The underground NPP carbon for the natural secondary forest,the plantation of larch,cropland and rangeland was 1.67～2.86 t·hm-2·a1,1.90～2.10 t·hm-2·a-1,1.38 t·hm-2·a-1 and 1.03 t·hm-2·a-1,respectively.The storage of aboveground biomass carbon of grass increased gradually from May to October.The storage of fine root biomass carbon was the highest in May,June and September for natural secondary forest,which was the lowest in August for rangeland,the highest in July and September for cropland and the highest in May,September and October for the plantation.