The invention discloses a machining method for a rear shaft neck of an aerial turbofan engine, and belongs to the technical field of precision machining of components for an aerial engine. The method comprises the following steps: blank machining, coarse machining, flow detection, semi-finishing, surface corrosion, thermal treatment, finishing, five-axis machining, excircle grinding, cleaning detection and machining completion. According to the machining method provided by the invention, problems can be discovered in real time during the machining process through multi-step machining and detection of branch operation, the deformation is controlled, the method is beneficial to discovering the defects of die forging blanks of the components, schemes of solving and dealing with the problems can be quickly performed, and the machining efficiency and quality of products are ensured. Moreover, the strength of the components can be ensured and the materials can be saved by adopting die forging blanks; moreover, the multi-step machining and detection of branch operation are adopted, and are also beneficial to controlling overhigh production cost caused by production defects; the machining method is further convenient to design special measuring tools and clamping tools, so that the machining efficiency and quality of components are ensured.