Abstract: The fatigue crack propagation process of titanium alloy CT specimen model under different initial crack lengths, load ratios, and maximum load conditions was analyzed using the extended finite element method. Results show that as the initial crack length increases, the fatigue cycle life of titanium alloy CT specimens decreases, the amplitude of stress intensity factor increases, and the crack propagation rate accelerates; As the load ratio increases, the fatigue cycle life of titanium alloy CT specimens increases, the amplitude of stress intensity factor decreases, and the crack propagation rate slows down; As the maximum load increases, the fatigue cycle life of titanium alloy CT specimens decreases, and the stress intensity factor amplitude increases, accelerating the crack propagation rate. This study will provide a certain reference value for fracture failure assessment of engineering components.