Crack propagation rates of FGH96 P/M superalloys with different heat treatments were tested and compared under fatigue/creep interaction at 650 ℃ in air. Influence of heat treatments on the crack propagation rates of FGH96 P/M superalloys was investigated. The results indicate that the crack propagation rates were decreased when increasing the solid solution temperature or salt bath temperature; the effect of solid solution temperature was greater than that of salt bath temperature. Lower aging temperature and shorter aging time also delayed the crack propagation rates; the effect of the aging temperature was greater than that of the aging time. In addition, the crack propagation rates were increased with the dwelling time prolonging, and its effect decreased with the aging temperature increasing.