Abstract:Using 16S rDNA clone library method, the bacteria composition of the Organic Matter-decomposing Inoculants A and B were investigated. The results indicated that: Sample A was clustered into 14 taxonomic operational units (OTUs),the dominant communities are Weissella confuse,Bacillus subtilis and Bacillus pumilus, which accounted for 28.6%,30.4% and 23.2%;Sample B was clustered into 43 OTUs,the dominant communities are Lactobacillus buchneri, Lactobacillus farciminis and Lactobacillus acetotolerans, which accounted for 18.03%,18.86% and 13.12%, respectively. The results had much difference from the samples' labels:there were not bacteria in the lable of sample A and only Bacillus pumilus was the same with the lable of sample B.This study showed that 16S rDNA clone library method has nicer application perspectives in analying the bacteria of microbial inoculant and its quality control.