Abstract: Currently the research on general layered rock slope have been quite thoroughly, but for thin-layer rock slope, due to its special form of rock mass structure, the drill core is always broken. It is difficult to collect rock samples which are comply with the laboratory test requirements thus we cannot acquire the physical and mechanical properties by conventional means, which directly affects the analysis of slope failure mechanism and stability. So it's necessary to take further study on this type of slope. This paper is based on a thin-layer phyllite slope in south Shaanxi, the natural and saturated gravity of strongly weathered and moderately weathered rock masses are respectively acquired by site gravity test and equivalent volume method. The natural and saturated uniaxial compressive strength of rock masses are determined by point loading test. For strongly weathered rock masses which are cut broken by structural planes, the strength is controlled by structural planes, and the shear strength is acquired by JRC-JCS method which is proposed by Barton. For moderately weathered rock masses, Hoek-Brown criterion which bases on RMR classification system is employed to weaken rock strength. The shear strength is estimated by weakening strength and the strength of structural planes. Meanwhile, based on the topographic and hydro-geological features of this slope, establish a two-dimensional model via M-C criterion to analysis the stress-strain characteristics and steady state under natural and heavy rain conditions, so as to reveal the failure mechanism and stability of thin-layer rock slope and provide a reference for analysis and prevention of slope of the same type.