Abstract: The biological oxidation capacity and change of microbial community structure of typical landfill cover soil cultured in situ by methane and trichloroethylene (TCE) were studied. The rates of CH₄ oxidation and TCE degradation were 0.20-0.87 μmol·g^-1 soil·h^-1 and 0.009-0.013 mg·L^-1·h^-1 among these landfill cover soils, respectively. The activity of CH₄ oxidation in Shandong landfill cover soil was higher than that in landfill cover soils sampled from Guangdong, Shanghai and Chongqing. The α-diversity and microbial community structure before and after co-metabolism degradation were then investigated in all landfill cover soils by Illumina MiSeq sequencing. The results indicated that bacterial Operational Taxonomic Units (OTUs) were assigned to 39 phyla, 85 classes and 562 genera in all the commented OTUs clustering. The dominant bacterial populations were Proteobacteria, Bacteroidetes, Chloroflexi and Acidobacteria and the sum of the proportion was over 77.4% in all landfill cover soils. In addition, total percent of γ-Protebacteria, β--Protebacteria, α-Proteobacteria, Actinobacteria and Acidobacteria was over 26.5%. Specifically, the relative abundances of Methylophilaceae_uncultured, Anaerolineaceae_uncultured, Arthrobacter and Pseudomonas increased obviously after acclimated by TCE. These results suggested that there were co-metabolism degradation with non-methane compounds and aerobic assimilation of TCE besides the widely-agreed co-metabolism degradation by methanotrophs.