A geographic information systems(GIS)-based slope stability analysis method is proposed based on the assumption of normal stress distribution acting on the slip surface. first, a three-dimensional slopestability analysis model based on grid column units is established. then, four equilibrium equations are derived under limit equilibrium condition. the normal stress distribution acting on the slip surface is analysed to construct a reasonable normal stress distribution approximatin function for solving the safety factor. moreover, a GIS-based extension module is developed. the accuracy and feasibility of the module are vefified by three typical cases.