Abstract: Based on three-dimensional scanning technology,the discrete element model of cement-stabilized steel slag with real steel slag shape is constructed by Particle Flow Code 3D. The sensitivity between macro and micro parameters of the sample is explored and the nonlinear regression equation is established. The uniaxial compression simulation tests are carried out on the samples with different steel slag contents. Combined with the custom programs such as contact calculation and crack location,the macro and micro mechanical properties and micro-crack evolution law of the samples during the failure process are analyzed from the aspects of strength and fracture damage. The results show that the peak strength is directly proportional to the tensile strength and inversely proportional to the porosity. The elastic modulus is greatly affected by porosity,effective modulus, bond strength and parallel bond friction angle. Poisson′s ratio is mainly controlled by porosity. With the increase of steel slag content,the elastic modulus and peak strength of the samples increase,the Poisson′s ratio decreases,and the post-peak stress curve steepens,showing obvious brittle failure characteristics. The fracture formation can be divided into four stages:initiation, propagation,convergence and penetration. With the increase of steel slag content,the fracture surface thickness of the sample increases,and the number of micro-cracks increases exponentially.