Abstract: The effect of δ-ferrite on the corrosion resistance of 1Cr17Ni2 stainless steel in different solutions was studied by weight loss rate testing, optical microscopy (OM) and scanning electron microscopy (SEM). The results show that δ-ferrite weakens the corrosion resistance of 1Cr17Ni2 stainless steel in FeCl₃ solutions, and δ-ferrite is the selective dissolution phase. In HNO₃+HF solutions, δ-ferrite enhances the corrosion resistance of 1Cr17Ni2 stainless steel, and tempered sorbite is the selective dissolution phase. The method of distinguishing and analyzing the corrosion surface micrographs to study the selective dissolution behavior of 1Cr17Ni2 stainless steel can also be used to find out the corrosive environment, and provide a basis for corrosion failure analysis and prevention.