The invention discloses a machining method for an aero-engine fuel main tube with an integrated branch oil tube. The machining method comprises the steps that firstly, the branch oil tube and a tee coupling are clamped and hooped through an electrode holder of automatic argon arc welding, a tungsten electrode of automatic argon arc welding is aligned to a welding seam for automatic welding, and seamless welding of the branch oil tube and the tee coupling is completed. The problem of interference of the electrode holder of automatic argon arc welding and the main fuel tube and the branch oil tube is solved, then the welded branch oil tube and the main oil tube are welded into a whole by an automatic welding method, and machining of the fuel main tube is completed. According to the machiningmethod for the aero-engine fuel main tube with the integrated branch oil tube, automatic welding of full position of the argon arc welding seam of the aero-engine fuel main tube is achieved, the problem of unstable quality of manual argon arc welding is solved; and the welding quality and machining efficiency of the fuel main tube are improved, the welding difficulty of the argon arc welding seamis reduced, and stability of welding quality is ensured.