Abstract: A zirconium modified surface alloying layer was prepared on 0Cr18Ni9Ti stainless steel by double-glow plasma surface alloying technology to improve the acid resistance of stainless steel in the special environment, and the structure of Zr-alloyed layer was examined, then an electrochemical corrosion comparison test of stainless steel substrate and Zr-alloyed layer samples were taken in 0.5 mol/L H₂SO₄, 0.5 mol/L HNO₃ and 0.5 mol/L HCl solution. The results show that the corrosion rate of stainless steel sample are 2.18, 9.73, 24.43 times as the Zr-alloyed layer in H₂SO₄, HNO₃, HCl solution; Surface corrosion of stainless steel sample is more serious, and only minor localized corrosion pitting is on the surface of Zr-alloyed layer sample. Alloying elements in the Zr-alloyed layer presents gradient distribution and a dense zirconium oxide passivation film is formed on its surface, so acid corrosion resistance of Zr-alloyed layer is improved significantly compared to the stainless steel substrate and it's more obvious in HCl solution than in the HNO₃, H₂SO₄ solution.