Abstract: Based on the analysis of the shape and material characteristics of the aluminium alloy guide pin in the landing gear project, the turning and milling methods of the workpiece were introduced, the machining parameters, cutting tools, measuring methods and the design ideas of the tool were described in detail, and the influence of the rough machining allowance on the final dimension accuracy of the workpiece was studied and illustrated. It had been proved by practice that the machining method involved can effectively control the deformation of the workpiece, can ensure the shape and dimension accuracy, and has targeted engineering significance.