In this paper, discrete element method (DEM) is used to investigate the strength properties and failure modes of QH-E lunar soil simulant at the low confining stress. The deviator stress-axial strain curves and volumetric strain-axial strain curves are obtained based on DEM simulations, which are basically consistent with the experimental results at the low confining stresses, and the lower confining stress is, the closer to the experimental curves will obtain. Moreover, for a given low confining stress, the effects of porosity and friction coefficient on strength properties of QH-E samples are discussed. The results show that the peak stress, residual stress and axial strain corresponding to the peak stress obviously decrease with the increase of the porosity, while slightly increase with the increase of the friction coefficient. Furthermore, the whole failure processes and failure modes at different low confining stresses are also observed by DEM simulations. The simulated results indicate that the V-type shear zone (double shear bands) is the main failure mode at the low confining stress, and then the V-type shear zone gradually changes to a single shear band (along the horizontal direction about 52o) with the increase of the confining stress.