Abstract: This study systematically explored the coupled effects of load magnitude （0.1−0.4 MPa） and direction （10°−90°） on the dynamic crack propagation behavior of rigid materials based on the AT1 phase field model. Numerical calculations revealed the dual control effect of load conditions on crack propagation behavior: the magnitude of the load significantly affects the crack propagation speed and final length, and the crack propagation exhibits a typical three-stage characteristic of initiation-steady state-decay, with 0.3 MPa as the critical pressure threshold; The direction of the load regulates the microscopic mechanism of crack propagation and anisotropic fracture behavior. The propagation speed in the 90° direction reaches 6mm/μs, which is 400% higher than that in the 30° direction. There is a sudden change in material response in the 60°−75° range, and high loads ≥0.3 MPa and vertical loads ≥75° can induce crack branching, and the branching time advances with the intensity of the load. The research results of this article provide a solid theoretical foundation for the safe design of engineering structures, emphasizing the need to avoid critical states by reasonably controlling load parameters, thereby effectively curbing the rapid expansion of cracks.