Fatigue crack growth behavior at 650℃ of a P/M superalloy FGH97, which was made by Argon Atomization (AA) + Hot Isostatic Pressing (HIP)process, was investigated. Comparison tests were conducted using a Russian EP741NP disk made of Plasma Rotating Electrode Process (PREP) + HIP process. The effects of different powder making methods, oxygen content, grain size and gamma prime size on the fatigue crack growth rate were evaluated. The results revealed that the fatigue crack growth behavior of AA + HIP processed FGH97 test disk has a lower crack growth rate compared with EP741NP disk, and disks with larger grain size, larger gamma prime size have lower crack growth rates, the oxygen content between 100~150 ppm range has no significant effect on the crack growth rate.