This paper presents results from a research initiative aimed at the γ′ precipitation behavior in superalloy FGH97 during continuous cooling from supersolvus temperature by Gleeble-3800 and heat treatment simulator furnace at cooling rates of 15~240 °C/min. The influence of cooling rates on γ′ size, paticle morphology and tensile strength is investigated. During cooling from supersolvus temperature γ′ nucleation and growth, even coarsening, simultaneously occur. However, ageing treatment seems to exert little influence on γ′ evolution. At the cooling rate of 15 °C/min a large number of secondary γ′ split and form square paticles with ~0.38 μm. Meanwhile, there are lots of small tertiary spherical γ′ around secondary γ′. As the cooling rate decreasing to 60 °C/min the size of secondary γ′ decreases to ~ 0.22 μm and the precipitation of tertiary γ′ is completely inhibited. The tensile strength tends to increase after an initial decrease with a decline of cooling rates, due to the combined influence of γ′ volume fraction, particle size and γ/γ′ mismatch.