Abstract: In order to study the law of crack propagation under different pore-fracture conditions, the crack propagation process, acoustic emission law and stress-strain curve under different crack inclination angle and different heterogeneous coefficient were numerically simulated by using RFPA software. At the same time, the results are compared with the experimental results. The results show that the cracks of the intact specimen are produced along the shear direction, while the cracks of the specimens with pores occur along the side of the crack tip and the orifice. The secondary cracks in horizontal direction and bifurcation at the prefabricated crack tip or the side of the orifice at the same time are produced through the specimens with wing cracks, and the heterogeneity coefficient affects the strike of the secondary cracks. Pre-ballast specimen with tensile failure in the late stage of the main and ballast stage, the tensile-shear combination is mainly destroyed, and the generation of secondary cracks is related to the shear failure. The cumulative energy of the acoustic emission and the acoustic emission increased slowly in the early stage; and rapidly in the later stage, the smaller the inclination angle of the pre-cast crack, the larger the heterogeneous coefficient, the greater the accumulated energy of the acoustic emission, and the stress time curves of the test pieces at different crack inclination angles and different mean values are all subjected to three stages. The existence of the porosity reduces the peak strength of the samples and affects the brittleness of the specimens. The results of the study provide some reference for further understanding the law of the pore-gap interaction.