Abstract: To study the influence of the heterogeneity degree on the mechanical behavior, failure mode and fracture development of brittle rock under uniaxial compression, the universal discrete element software was used to construct some numerical specimens with an assemblage of Voronoi blocks. FISH language and the Weibull distribution function were combined to achieve the heterogeneous distribution of block elastic modulus and tensile strength on block contacts. Some uniaxial compression simulation tests of the brittle granite with various homogeneity coefficients were implemented. The results show that the compressive strength and elastic modulus of the specimens both increase with the increasing homogeneity coefficient, while the deformation before failure decreases with the increasing homogeneity coefficient, but the three indices all tend to stable. The specimens show X shape conjugate shear failure in macroscopic level, and the mesoscopic failure mainly consists of tensile and shear fractures between and in the crystalline grains. Tensile fracture propagation takes the dominant position before the peak stress and after that the shear fracture dominates the fracture development. For the specimens with smaller homogeneity coefficients, the fracture distribution and propagation were more dispersive and the cumulative length of the fractures is smaller, too. But the tensile fracture length shows a negative correlation with the changing homogeneity coefficients when the axial strain is less than 0.2%. This phenomenon indicates that tensile fractures start to initiate and propagate in early compression stage of specimens with high heterogeneity degrees. In addition, the mechanical behavior and fracture development law between the specimen with homogeneity coefficient of 6.0 and the homogeneous specimen are very close, so the value of homogeneity coefficient should not be too large when simulating heterogeneous rocks using Weibull distribution.