Abstract: The Kettleman Hills landfill, which had a slope-stability failure in March 1988, is a typical complex ("Valley" type) landfill, and the two-dimensional analysis is difficult to evaluate its stability. At present, the limit equilibrium method is mostly adopted in the three-dimensional stability analysis of the Kettleman Hills landfill. However, since the conduction of the failure mode does not need to satisfy the strict conditions (kinematically admissible), it is unable to identify whether the results are safe or risky, and even whether the failure mode is reasonable. Thus, based on the upper-bound limit analysis method, the two-dimensional, quasi-three-dimensional and three-dimensional failure mechanisms are conducted and verified though the comparisons with the results of the existing literatures and numerical simulations. The two-dimensional and quasi-three-dimensional failure mechanisms are similar and easy to conduct, so they are convenient for rapid preliminary stability analysis of the landfill. The three-dimensional multiple-block failure mechanism is difficult to conduct and needs large computation, but it can reflect the actual destruction of the landfill and is suitable for a detailed analysis of the landfill.