In order to investigate the microstructure evolution of 925 alloy during homogenization and solution treatment, nickel-based superalloy 925 alloy ingots of vacuum-induction-melting and electroslag-remelting were prepared and homogenization and solution tests were carried out. The microstructure and precipitations of 925 samples were studied by optical microscopy,scanning electron microscopy,and energy dispersive spectroscopy．It is found that there exist phases such as TiN, MC, σ phase, γ′ phase and η phase in the ingots， and σ phase, γ′ phase and η phase can be remelted in 1160℃ after 5h. After homogenization at 1160℃ for 20 h,this segregation can almost be eliminated. In solution treatment range of 950℃ to 1070℃, the amount of grain boundary precipitation of M₂₃C₆ decreases gradually and the grain size increases quickly.