Abstract: In the old-growth Larix gmelini forests, natural seedlings and their microhabitat were studied by using line transect method.The quadrats, in which the number of seedlings and habitat variate were measured,were set up along the line.The results show that forest floor plays the most important role,shrub layer the second,and light the last. As for the forest floor,the litter, root layer and mosses occupy a remarkable position. The litter inhibites the mosses developrnent.The major factors that inhibit natural regeneration were grasses in L. gmelini-Betula fruticosa forest,moss thickness in L.gmelini-Alnus mandshurica forest,moss thickness and root layer in L.gmelini-Ledum palustre forest.