Abstract: The orthogonal experiment method was used to carry out milling experiments on 7A65-T7451 aluminum alloy, and a large number of surface roughness process parameters were obtained.The extreme difference and average value of the experiment data were analyzed, and the order and trend of the influence of each parameter on the surface roughness were determined.Based on multiple linear regression analysis, a predictive model of surface roughness was established, and also the model was tested for errors.The prediction model provides a basis for the reasonable selection of milling parameters of 7A65-T7451 aluminum alloy, and has certain significance for reducing surface roughness and increasing fatigue life when 7A65 aluminum alloy is used in aerospace structural parts in the future.