Abstract: The orthogonal test method is used to analysis nine samples with different milling parameters. The surface quality parameters of the samples are measured by the hardness tester and three-dimensional profiler. Then the fatigue test machine is used for low-cycle fatigue comparison tests, and finally SEM is used to analyzes the fracture of the sample. Fatigue experiments show that the effect of cutting speed on low-cycle fatigue life is the most, followed by the depth of cut, and the effect of feed rate is the smallest. The internal plastic deformation of the specimen under cyclic loading above the yield strength causes the initiation and propagation of fatigue crack sources, which is the main reason of fatigue fracture. Mathematical model is established to estimate the length of low-cycle fatigue life.