Abstract: There were rich seeds of Larix gmelini dispersing naturally in the soil of old-growth larch stands after a mast year. Vital seeds in the soil amounted to 190～320 grains/m2, showing a significant difference among different forest types. Seeds existing in the upper layer of the soil within a scale of 2～4cm accounted for 70%～80% of the total amount. The vitality for most seeds that could germinate rapidly under optimal conditions would last no more than one year, seldom over two years. It was quite evident that the seed bank of Larix gmelini in the soil was of the interrupted type. Meanwhile, by a test of sowing seeds artificially, we got a result the same as above. The pathogens in the soil was the main reason causing death to seeds.