The discrete element method(DEM) is a numerical simulation method based on non-continuous medium mechanics, which can effectively analyze the macro and micro mechanical behavior responses of cemented granular materials. By using the three-dimensional discrete element commercial software PFC3D, a series of conventional triaxial compression tests for cemented sands with different cement contents and different confining pressures were simulated based on the microscopic cement contact model BPM to study the macro and micro mechanical behaviors of cemented sands. The results of simplified simulation showed that, compared with the pure sand specimen of the same initial void ratio, shear strength of the cemented sands was higher, the tested stress strain curve showed obvious strain softening, volumetric curve showed the dilatancy. The peak strength increased and the softening and dilatancy enhanced with the increases of cement content. With the increase of confining pressure, the peak strength increased and the dilatancy reduced; but the softening kept unchanged. In addition, the internal friction angle and the cohesion of the specimen were affected by the cement content and the confining pressure.