Abstract: Studied here in the article are the status characteristics of the precipitate phases of a certain corrosionresistant nickel-based alloy tube as developed at three different solid solution temperatures，i.e.，1 020℃，1 080℃ and 1 130℃.The analysis result shows that a large number σ phases rich in Cr and Mo got formed in the grain boundary，after the said alloy is annealed at 900℃ for 2 hours.And after being solid solution treatment at 1 020℃ for 1 hour，grain boundary σ phase still remains in large quantity.Due to solid solution treatment at 1 080℃ for 1 hour，most of the σ phase is eliminated，but there still remains a small amount as residual in the grain boundary. Nevertheless，thanks to solid solution treatment at 1 130℃ for 1 hour，the residual precipitate phase is completely eliminated，thus provides excellent microstructure condition for assuring corrosion resistance of the alloy pipe.