Fatigue failure is the main failure mode of mechanical failure. The effects of mirror milling and chemical milling on fatigue performance of 2024 Al alloy were analyzed in this paper. The fatigue properties of 2024 Al alloy were explored at 130 MPa, 140 MPa and 149 MPa stress levels by using group test method. The results show that the overall stability of the mirror milling is better than that of the chemical milling, the tensile strength is comparable, and the standard deviation of the life of the mirror milling test pieces is about three times that of the chemical milling; the median logarithmic fatigue life of the mirror milling test pieces is better than that of the chemical milling at all three stress levels. The relationship curves between stress level and fatigue life of 2024 Al alloy at 50%, 95% and 99.9% survival rates are obtained, which provide a reference for quantitative analysis of the effects of mirror milling and chemical milling processes on fatigue performance of the material.