2205/Q235B clad steel plates were fabricated using a thermal simulator. The metallographic microscope, scanning electron microscope, energy-dispersive spectrometer, shear test, electrochemical corrosion test and acid immersion test were used to study the influence of the pass reduction ratio on the microstructure and properties of 2205/Q235B clad steel plate. The results show that the clad steel plates had a good bonding surface when the pass reduction ratios were between 16.3％and 36.0％. There existed the mutual diffusion effect of elements near the bonding surface, which caused the long austenite strip on the side of 2205 stainless steel and the decarburization layer on the side of Q235B low-carbon steel. The transformation of δ ferrite to γ austenite and the generation of the decarburization layer were promoted because of the lower pass reduction ratio. The corrosion resistance of 2205 duplex-phases stainless steel worsened by the decrease inδferrite content. The increase in the decarburization layer thickness made the shear strength of the clad steel plates reduce from 453 to 390 MPa. The potential of the decarburization layer was lower than that of 2205 stainless steel and Q235B low-carbon steel, which was easily corroded in the corrosive medium.