Silt as landfill cover soil and two kinds of biochar as soil amendment, respectively woodchip biochar and rice straw biochar, were used in this study. Batch test with duration up to 30 days were carried out on silt and biochar amended silt samples to measure their methane oxidation capacity. The influence of moisture content on methane oxidation was also investigated. The experiments demonstrated that all biochars increased the silt methane oxidation capacity 2.5 times or so. All soil samples were barely methane oxidation when moisture content is 10%. The optimum moisture content range for methane oxidation of the silt and different biochar amended silt was different, all biochars increased the optimum moisture content range for methane oxidation of the silt. The moisture content range for double open of soils were predicted by compaction curve in this study, the predicted results showed that the moisture content range for double open of soils was more widely ,while the optimum moisture content range for methane oxidation of soils as more widely. Biochars increased the moisture content range for double open of the silt, so that increased the optimum moisture content range for methane oxidation of the silt.