Abstract: By the use of BIOLOG microplate method， the soil microbial diversity characteristics of primary Korean pine forests and man\|made forest in Liangshui National Nature Reserve， Lesser khingan were studied. The results showed that the soil microbial AWCD values of the forest\|type varied with soil depth and seasons: in the surface and 0\|10 cm layer of soil， it was the highest in Korean pine forest and Tilia amurensis forest; in the 10\|20 cm layer of soil， it was the highest in Xingan larch forest in spring， summer and autumn， while it was the highest in Tilia amurensis forest in winter. The soil microbial diversity indexes of all soil layers were the highest in Tilia amurensis forest， and were significantly higher than those of man\|made forest. So we concluded that the soil microbial diversity of primary Korean pine forest was richer than that of the others.

Key words: Lesser khingan, BIOLOG, microbial diversity, AWCD value, diversity index