Abstract: By the uniaxial compression test of slab sandstone specimen containing pre-existing single crack of different dip angles, the influence effect of crack dip angle on the deformation and failure characteristic, AE evolution law and crack propagation evolution law of brittle rock were deeply analyzed from macroscopic and mesoscopic perspectives, meanwhile, the failure mechanism was revealed. The results show that: when the crack angle was small (0°≤α≤30°), the stress-strain curve exhibited a “saw tooth” shape and failure mode was primarily splitting failure; the wing crack firstly sprouted in the middle of the initial crack, then the propagation and coalescence of secondary tensile crack caused the ultimate fail of the specimens, therefore, AE signal during the whole compression process was more dispersed; with the increasing of flaw angle (30°<α<90°), the number of stress dropping decreased, the peak strength and elastic modulus increased continuously, and the failure mode was primarily shear failure; the initiation position of wing crack firstly appeared in the initial crack tip, and the crack initiation strength and crack initiation strength ratio increased gradually, then, the secondary crack transferred to shear crack, which made the AE signal tended to concentrate; for the crack angle of 90°, the stress-strain curve was very smooth, the specimen failed instantaneously and caused AE signal concentrated abnormally before the crack initiation of the initial crack, and the fail mode was splitting damage, which was basically consistent with the complete sample.