Abstract:: Thermal-calc thermodynamic software was used to calculate the precipitates in GY200 equilibrium conditions.The microstructure, performance, carbides and γ" phase evolution of GY200 nickel base alloy for the blades of an advanced super supercritical power station at 700 and 750 °C with different aging times were studied by means of metallography, scanning, and chemical phase analysis. The results show that the strength increases significantly after aging, and the impact performance decreases slightly. The carbides mainly consist of M23C6 and MC phases. The replacement of Mo in Waspaloy by W decreases the precipitation tendency of M6C. The content of M23C6 phase increased with the increase aging time, and the carbides separated out as chains and lamellae in the grain boundary. The amount of MC phase began to decrease after aging for 3000 h. The amount of γ" phase increased after aging at 700°C for 3000 h, stabilized after 5000 h, and remained basically unchanged at 750 °C. The γ′ phase has good thermal stability at 700°C with a low coarsening rate. The coarsening rate at 750°C is higher and the diameter of γ′ is about 100nm after aging at 5000h.