Abstract: FGH101 superalloy was welded by inertia friction welding (IFW).The microstructure and mechanical properties of the FGH101 alloy IFW joint were studied.The results show that the joint is well formed and almost has no flash.The weld nugget zone (WNZ) of joint consists of exquiaxed grains with little γ' strengthening phase, and coarse grains and fine grains coexist and have irregular morphology in the thermo-mechanically affected zone (TMAZ) of joint.The microhardness of the joint presents typical "M" distribution.The hardness of the WNZ of the joint is the highest and the hardness decreases in the central of the WNZ.And the microhardness improvement is not significant after heat treatment.The tensile strength of the joint at room temperature is about 1600 MPa, which is 98.4% of that of the base metal, and the yield strength of the joint at room temperature is about 1178 MPa, which is 98.6% of that of the base metal.While the tensile strength of the joint at 750 ℃is about 1208 MPa, 96% of the base metal, and the yield strength of joint at 750 ℃is about 1037 MPa, 96% of the base metal.