The low cycle fatigue properties with Stress and Strain constant-ampitude controlled test methods，the tensile properties at 650℃, the microstructure at different positions and the fatigue fracture of an FGH97 superalloy disc, which was manufactured by Argon Atomization (AA) + Hot Isostatic Pressing (HIP)+Heat Treatment process, were investigated. The results reveal that the grains size and the γ′ weresimilar at different positions. The tensile strengthes at 650℃ were between 1325 to 1340MPa, and the Yield Strengthes were between 1010 to 1025MPa, which are relatively stable. The average Nf by Stress-controled was 200000 cycles at different positions, Weibull distribution η was 215194.The effect of the inclusion size of less than 80μm on Nf was not obvious. The Weibull distribution η of the Strain-controled was 14622 when the Nf was less than 20000 cycles, and 44342 when Nf was more than 20000 cycles. The variation of inclusion area leads to the difference of characteristic value beta of Nf Weibull distribution. The crack source of fatigue fracture was mainly the inclusions, and the fracture morphologies were rather similar. The fatigue by the strain controled test was more sensitive to the inclusions.