Abstract: Heat treatment with different cooling rates after solution was conducted on FGH96 powder metallurgy nickel-superalloy by using program-controlled furnace with a compressed air-cooling system. A scanning electron microscope was used to analyze the influence of such heat treatment on the microstructure of the alloy. The results indicate that,high-temperature heat treatment causes damage to the sample surface, including the surface oxide layer and’enhanced phase-poor areas. The cooling rate after the insulation phase of the solid solution heat treatment has a significant impact on the morphology and size of the’reinforced phase in the FGH96 alloy. The faster the cooling rate, the smaller the size of the’reinforcement phase, the two making into a power function relationship.