Abstract: The ecological series of soil animals in southern Xiao Hinggan Mountains was studied Xiao Hinggan Mountains. Eight sample plots were selected according to a series of equal altitude difference, which belonged to different vegetation types. By investigating and analysing soil animals of every sample plot, It can be seen that the altitude was the key one among the factors of ecological series. Both the groups and indviduals of soil animals almost increased with increasing altitude, which opposited to ordinary cases, resulting from special micro climate of the studied area. Both the groups and individuals of soil animals of Picea and Abies forest were lesser than other communities.