Abstract: A new calculation method of electron vacancy number in Ni-based high-temperature alloy was introduced, and then to predict microstructure stability and precipitation trend of topologically close-packed (TCP) phase in five kinds of typical Ni-based high-temperature alloy. The results show that it was accurate to predict precipitation trend of TCP phase in the substrate of Ni-based high-temperature alloy. However, it was unfit for predicting the precipitation trend of TCP phase in coating diffuse zone.