In order to optimize the milling parameters in milling of TA15 titanium alloy using carbide end cutter, and to control the surface integrity and improve the fatigue life of components, the effects of machined surface integrity on the fatigue life of TA15 titanium alloy were investigated through milling experiments, surface integrity tests, and fatigue tests. The results show that the surface roughness R_a of TA15 titanium alloy is 0.148–0.245 μm after milling, the maximum residual compressive stress is detected on the surface, the depth of the residual compressive stress affected layer is approximately 30 μm, and the depth of the hardened layer is approximately 70 μm. The fatigue life increases with the decrease of surface roughness and the increase of residual compressive stress. The optimal combination of milling parameters: milling speed 40 m/min, feed per tooth 0.03 mm/z, and the maximum fatigue life is 4.044×10⁵ times. The tensile fracture of the machined TA15 titanium alloy is ductile fracture with deep dimples.