Abstract: Ni-based alloy cladding layer was prepared on the surface of HT300 gray cast iron by multi-step induction cladding method. The microstructure, phase composition and corrosion behavior in H₂SO₄ solution of the cladding layer were studied. The results show that the cladding layer was metallurgically integrated with the substrate. The cladding layer mainly consisted of γ-Ni,Ni₃Si,Cr_1.12Ni_2.88,Ni₃B, Cr_15.58Fe_7.42C₆ and other phases. There was a passivated procedure in the electrochemical corrosion of the cladding layer. The free corrosion current density and corrosion rate of the cladding layer were far below those of gray cast iron. The cladding layer/H₂SO₄ solution corrosion system had a higher total resistance value. Ni₂O₃ with passivation effect was formed on the surface of cladding layer in H₂SO₄ solution, and improved the corrosion resistance of the cladding layer significantly.