The invention discloses a milling method of a double-sided frame part. The method comprises the following steps: S1, roughly milling the upper surface and the lower surface of a blank to respectively obtain a frame surface A and a frame surface B, and enabling the process allowance of the frame surface B to be greater than the process allowance reserved by the frame surface A; S2, performing unstressed clamping, performing finish milling on the frame surface A, and
machining to the theoretical size without the process allowance; and S3, performing finish milling on the frame surface B, using the top faces of ribs and edge strips of the frame surface A subjected to finish milling in the step S2 for positioning, and when a web plate is machined, milling the web plate from inside to outside by adopting axial milling without layering and taking the center of the sash of the frame surface B as the starting point. According to the method, the ribs and the edge strips of the frame surface A subjected to finish milling are used as positioning references for positioning, and an additional clamp is not needed; large process allowance is reserved when the frame surface B is obtained through rough milling, and the
machining strength of the finish-milling frame surface is guaranteed; and axial milling is adopted, layering is avoided,
machining is conducted from inside to outside in sequence, the problem that in the prior art, web plate machining vibrates and the web plate is damaged is solved, and the overall machining stability of the web plate is guaranteed.