Abstract: The use of bio-cover composed of aged refuse to reduce emission of greenhouse gases (CH₄, N₂O and CO₂) from landfills was studied in depth, analyzing roles of environmental factors in CH₄ emission and CH₄ oxidation relative to thickness of the aged refuse cover. Results show that when temperature varied in the range of 5-45℃, the mean CH₄ oxidation rate of aged refuse was 2.35 times that of clayey soil and 4.71 times of that of sandy soil, and it increased with rising temperature and peaked at 35℃. When moisture content in the cover layer was maintained in the range of 16%- 24%, all the three covers peaked in CH₄ oxidizing capacity. The mean CH₄ flux from the sandy soil cover and the semi-mineralized refuse cover was 329.8 and 91.7 times of that from the pure aged refuse cover, respectively. Addition of aged refuse in the cover would increase the flux of N₂O oxidation. The mean flux of N₂O emission from the pure aged refuse bio-cover was 2.1 times (P<0.05) and 3.5 times(P<0.05) of that from the semi-aged refuse cover and sandy soil cover, respectively.