Abstract: The distribution laws of soil microorganism in the soil of L. chinensis grasslands were investigated in Northeastern China Plain, and the effects of soil features on them were analyzed. The results showed that the amount and the net biomass of microorganism was the biggest in the soils under L. chinensis community and weed community, the smallest in the soil covered by the Puccinejjia tenuifora community, and moderate in the soil of Cleistogenes squarrosa community. Among the measured 11 soil factors, the interactions between pairs of soil total N-total P, active organic matter-total P, pH- total P, pH-total K, total K-total P, active organic matter-total N, active organic matter-total K, organic matter-total N were distinct, with the correlation coefficients of 2.90--5.94. The direct effects of total P,N, K, pH and active organic matter on the microbial biomass were significant, with the path coefficient of 2.02--6.15.