In order to study deeply the initial pressure cracking problem of coalbed methane wells under hydraulic fracturing conditions. Firstly, based on the principle of fracture mechanics and the maximum circumferential stress criterion, the original geostress field and fracturing fluid permeability field of the reservoir are analyzed, the fracture steering control model is established. Secondly, considering the complex stress boundary conditions of the turning fracture surface, the crack propagation expansion model is established by displacement discontinuity method. Finally, the influence of perforation angle, geostress difference and construction displacement on pressure crack steering expansion are considered. Combined with the on-site construction parameters of encun mining area in Jiaozuo, the crack deflection angle and deflection distance were calculated separately. results show that the difference between the perforation angle and the ground stress has a great influence on the steering crack in the near-well area, while the influence of the fracturing fluid displacement is small. When the perforation angle or the ground stress difference is small, the pressure crack deflection distance is large, and the curvature of the formed crack is also small, the reverse is also true. Compared with the numerical simulation results using XFEM software to simulate the crack steering expansion mechanism, the simulation results are in good agreement with the theoretical values, which verifies the correctness of the model. Research results can provide theoretical guidance for field control of directional perforating hydraulic fracturing.