Abstract: To study the failure mode and fracture development of brittle rock under uniaxial compression, the mineral composition and content were tested through polarized microscope. The basic mechanical parameters of granite were obtained through laboratory tests. The numerical specimen of granite was built based on the PFC^2D software and random particle cluster method. After parameter calibration, the simulation results coincide with the laboratory tests well. FISH programs were compiled to capture the crack development and acoustic emission events during the compression progress. The results show that granite is a typical heterogeneous brittle rock, which has no yielding stage before peak and has no residual stage after the peak. The main failure mode is splitting damage, both tensile and shear fractures show up in the specimen. Tensile cracks are the main crack type and appear earlier than the shear cracks. The acoustic emission events show that a small amount of damage appears during the initial compressive stage, which is manifestation of the heterogeneous mineral strength. Plenty of damages appear before the peak, which results in the quick coalescence of micro-cracks and forms macro-failure fracture. This is the main reason for the instant burst of the granite after peak stress.