[Objective] To evaluate microbial biodegradation, three kinds of soil, swamp, orchard and farmland were selected. And to find dominant microbe that can degrade the PLA, we characterize the different of abundance, diversity and community structure of the three microbial strain. [Methods] The residual degraded PLA were analyzed by SEM, the tensile strength, elongation at break and CO2 generation analysis. And characterize the different of abundance, diversity and community structure of the three kinds of soil by using pyro-sequencing. [Results] The PLA biodegradation in swamp, orchard, and farmland were 13.7%, 10.6%, 4.5%, respectively. The taxonomic analysis of the pyro-sequencing data was grouped into 9 different phyla and 16 different class. [Conclusion] By comparing the microbial community of three kinds of soil, Proteobacteria and Bacteroidetes were the two most dominant phylato degrade the PLA. Flavobacteriaceae, Comamonadaceae and Cytophagaceae were the three most dominant class to degrade the PLA. The result provides scientific basis for the study of microbial diversity and community structure in biodegradation of PLA.