As the candidate materials for advanced ultra-supercritical power plants, 617 alloy has superior mechanical properties and resistance ability against oxidation at a high temperature. In this paper, equilibrium precipitated phases of 617 alloy were calculated by Thermo-Calc software. The results show that the equilibrium phases include γ′, σ, μ, M6C and M23C6. The amount of γ′ is more sensitive to Ti than Al. Furthermore, this paper analyzed the microstructure features of 617 alloy as standard heat-treated. It is shown that 617 alloy has equiaxed grains and continuously precipitated carbides which are observed along the grain boundary. After solution treatment (1180 oC/1 h), part of the carbides re-dissolves and carbides become discontinuously distributed at the grain boundary