Abstract: The isothermal treatment experiment was conducted on GH4738 alloy with different chemical composition,and the influence of alloy composition on the phase dissolution law was investigated. The results show that the content of Al+Ti plays an important role in determining the dissolution of γ’ phase. The dissolution temperature of γ’ phase increases with the increase of Al+Ti content. In addition, the elements of Mo, Cr and C also affect the dissolution behavior of γ’ phase according to supersaturation of Al and Ti in the matrix. While the Mo and Cr content in the matrix is high, which can decrease the solubility of Al and Ti in the matrix and then the dissolution temperature of γ’ phase is increased as a result. The dissolution temperature is also influenced by element C according to the formation of carbide with Al and Ti.