The invention provides a machining method for a precision inner cavity thin-wall integral centrifugal impeller of an aerospace engine. The machine method comprises the steps of material preparation, blank rough outline turning, semi-fine profile turning, blade type rough milling, natural failure, profile 1 fine milling, drilling, blade type fine milling, blade profile 2 fine milling, clamp repair,dynamic balance, fluorescence inspection and final inspection. According to the machining method for the precision inner cavity thin-wall integral centrifugal impeller of the aerospace engine, in particular to the machining of a centrifugal impeller of a high rotation speed engine used in an aerospace vehicle, an ultra-thin multi-curved surface blade with thickness of 1.2mm can be machined, the blade does not deform during the machining process, the residual height of a hub is ensured, the knife mark in the direction of air flow is machined; meanwhile, the extremely high coaxiality of inner holes in the two end surfaces of the hub and the micron accuracy of the machining of the inner holes in the large end surface of the hub can be ensured, and the requirements of very high dynamic balance, dimensional accuracy and shape and position tolerance of parts can be met.