A series of uniaxial compression experiment on the granite with the pre-existing flaw were carried out to study the influence of the inclining angle α of the pre-existing flaw on the progressive failure of brittle rock. The paper firstly summarized and discussed the axial stress-radial strain curves of progressive failure process, then analyzed the stress thresholds affected by pre-existing flaw and inclining angle α crack initiation stress σci, crack damage stress σcd, peak strength σf; stress-strain curves recorded by the strain gauges and the influence mechanism of surface flaw propagation of rock specimen. The experimental results show that in the loading test process of rock specimen with pre-existing flaw, the difference of inclining angle α is the main factor affecting the rupture pattern of brittle rock. So in the engineering applications of brittle rock with joint and fracture, the analysis on axial stress-radial strain curves can play the guiding role for the designs of underground excavation method and support form.