Abstract: The strain softening model and the null model in FLAC^3D code are adopted respectively to describe the mechanical behavior of the rock and crack, and the superfine element division method is adopted to divide the calculation model to simulate the crack propagation. This numerical calculation model is adopted to study the effect of crack length, inclination, and number on the crack propagation path and rock mass mechanical behavior under uniaxial compression. The calculation results are as follows: the uniaxial compressive peak strength decreases with the increase of crack length, and the occurrence position and propagation path of the secondary wing crack vary greatly when the crack length is different. The occurrence position and propagation path of the wing crack vary with the crack inclination. The peak strength of the sample varies when the crack inclination changes from 0° to 75°, which changes according to the parabola, and it is the least when the crack inclination is 30°. The crack number has a large effect on the crack propagation path and the sample’s failure mode, and the peak strength of the samples gradually decreases with the increase of crack number.