A 9-story brick-concrete building rapidly collapsed due to a landslide in Wulong County, China, on May 1st, 2001.The failure took place at the beginning of the rainy season. This paper discusses a number of scenarios to highlight the background geology, possible causes and mechanisms of the rapid movement, as well as the possible perched water conditions and the influence of man-made changes in the morphology. Of particular importance are preceding some related back analyses. For this, at first, a 2-D rigid-body limit equilibrium analysis is carried out in the present paper considering various related loads applied on the slope. Then, based on the geometric data investigated in the field and assuming the slide mass holding limit equilibrium, the shear strength parameters are back calculated out. The parameters are further used for back analyses of the landslide in order to explore the cause of landslide occurred through changing the cut-slope shape and groundwater table. The presented spreadsheet method is another contribution from this paper. Through the work, the authors conclude that apart from possible defects in the structure, it is certain that the landslide initiated the building collapse. Intense rainfalls must have increased water content, and hence fluidity of sandy clay intersected in the beds and layers of the sandstone. The process of excavation prior to building construction may have participated in the loss of stability.