Abstract: The in-situ aeration technology has advantages in accelerating landfill stabilization. A clear understanding of the evaluation of landfill stabilization under aeration is significant to the design and operation of an aeration system. However, the existing indices are numerous and varied. Considering the sensitivity to reflect the stabilization process and the accessibility to be monitored, five indices, oxygen utilization rate, normalized BOD/COD, nitrogen removal efficiency, biodegradation degree, and relative settlement rate, are selected to indicate the landfill stabilization from the perspective of gas, liquid and solid phases, respectively. Given the results of numerical simulations, the stabilization process of landfill under aeration can be divided into three phases: aerobic transformation, semi-stabilization and post-stabilization. After obtaining the corresponding weights of five indices, the membership functions of five indices in three stabilization phases are developed. Using the fuzzy theory, the evaluation method for landfill stabilization is established and applied to an in-situ landfill aeration case.