The invention belongs to the technical field of thin-walled part machining, and discloses a machining method of a stator inner ring thin-walled part. The machining method comprises the following stepsthat 1, a rough blank of the stator inner ring thin-walled part is placed on a lathe for being clamped, and by adopting an axial clamping mode, the left end face is supported and the right end face is pressed by using a tool; 2, rough machining is conducted on an outer circle and the end faces, and the 0.2 mm of machining allowance is left for both the outer circle and the end faces; 3, rough machining is conducted on the outer edge part of an inner hole by using an 80-degree inner hole cutter, and the 0.5 mm of allowance is left; 4, rough machining is conducted on the corner groove part of the inner hole by using a 35-degree inner hole cutter, and the 0.5 mm of allowance is left; 5, rough machining is conducted on the lower inner wall and the taper part of the inner hole by using a 35-degree end face cutter, and the 0.5 mm of allowance is left; 6, rough machining is conducted on the upper inner wall part of the inner hole by using the 80-degree inner hole cutter, and the 0.5 mm of allowance is left; 7, rough machining is conducted on an inner groove of the inner hole by using the 35-degree end face cutter, and the 0.5 mm of allowance is left; 8, the steps of 2 to 7 are repeated,semifinishing is conducted on the stator inner ring thin-walled part, and the 0.2 mm of allowance is left; and 9, the steps of 2 to 7 are repeated, and finish machining is conducted on the stator inner ring thin-walled part until the size is met. Deformation in the machining process is small, the ellipticity after machining is completed is controlled within 0.03 mm, and correction is not needed.