Abstract: Uniaxial compression experiments were carried out for granite specimen with pre-existing cracks. Variation laws of rock strength and elastic modulus under different crack angles were obtained， and the crack propagation process was recorded. The calculation model for rock particle flow under different flaw inclinations was established and the micro-parameters of calculation model were calibrated based on the laboratory testing results. Crack information during the crack propagation process was extracted by FISH language and was also analyzed in detail. The results show that with the increase of crack inclination， both the crack initiation stress and initiation angle increase continuously. The crack propagation types change from wing-crack-dominated to secondary-crack-dominated. Through the analysis of crack aggregation coefficient， it is found that with the increase of crack angle， the curve of crack aggregation coefficient changes from smooth to tortuous， and the crack propagation path is under the transition from concentrated to decentralized.

Key words: pre-existing crack, PFC2D, uniaxial compressive, crack propagation, fractal analysis