Abstract: At the meso-scale, the digital image processing technology is adopted to characterize the heterogene- ity of granite caused by different distributions, sizes and shapes of quartz, feldspar, mica, etc., combining with RFPA-DIP to establish a numerical model of flawed granite. The model can reflect the real meso-scale behaviors of material accurately. The simulation tests of conventional uniaxial compression are carried out, the influences of diverse mineral particle structures and flaws on the meso-fracture behaviors are studied, to reveal the realistic failure process and final failure mode based on different numerical models under the external load. It is shown that the influence of the flaws on the strength of the sample is more significant than that of the transformation of the mineral particle structure. The existence of flaws weakens the influence of the particle morphology on the strength of granite; the flaws and the structures of mineral particles have a direct influence on the initiation and the propagation of crack and the final failure mode of samples, the spatial structure of mineral particles and flaws is the main factor for the complex failure modes of the rock. The inner-microstructure and the flaws of samples influence the crack initiation stress level, and the existence of flaws has a more significant effect on the crack initiation stress.