Abstract: The internal hoop stress within a small nickel-based superalloy inertia friction welding joint and the internal hoop and axial stresses within a middle-size inertia friction welding joint were measured with the contour method and the internal stress distribution characteristics were discussed. The results show that the internal stress within the small specimens and narrow welds can be measured with the contour method and the steep and full internal residual stress distribution can also be obtained with the proposed method. The hoop stress in inertia friction welding joint varies severely along the axial direction and distributes uniformly along the hoop direction, while presents a nonuniform distribution across the thickness. At the weld center line, the hoop stress near the outer surface is larger than that near the inner surface, compressive axial stress presents near the outer surface and tensile axial stress arises near the inner surface. In addition, the axial stress varies linearly along the thickness.