The invention provides a machining method of a cabin section work-piece. The work-piece comprises end faces. The method comprises the steps of: determining the planeness of the end faces by taking the end faces of the work-piece as benchmarks; determining a rough machining center of the work-piece by taking pin holes and bottom holes in the end faces as benchmarks; carrying out rough machining on a profile of the work-piece and detecting a machining allowance of each end face; carrying out finish machining on the profile of the work-piece by using a diamond milling cutter according to a preset size; determining a finish machining center of the work-piece by taking the finish-machined profile as a benchmark; carrying out side-edge cutting and bottom-edge cutting on the end faces and end face sealing lug bosses by using a diamond coating milling cutter; carrying out boring-machining on the pin holes in the end faces; pressing out notch edges of a notch by using a pressing plate; and carrying out segmental machining and layered machining on the notch with a preset cutting step length by using a spiral cutting method. Thus, by using a benchmark conversion machining method, the problem of non-uniform wall thicknesses caused by machining deformation in a single benchmark is solved, and the phenomena of scaling-off, breaking-up and delaminating appearing during machining are avoided.