The invention discloses a stainless-steel and carbon-steel composite plate and a preparation method thereof. The stainless-steel and carbon-steel composite board is manufactured by stacking and compositing of a carbon-steel plate, a stainless-steel plate, a stainless-steel plate and a carbon-steel plate in sequence, wherein the carbon-steel plate comprises the following metal components in percentby weight: 0.15-0.20% of C, 0.19-0.35% of Si, 0.5-1.0% of Mn, 0.02-0.025% of S, 0.023-0.025% of P, 0.04-0.06% of Cr, 0.02-0.05% of Nb, 0.04-0.06% of Al, 0.40-0.60% of Ni and the balance of Fe; the stainless-steel plate comprises the following metal components in percent by weight: 0.07-0.075% of C, 0.65-0.75% of Si, 1.4-1.8% of Mn, 0.003-0.01% of S, 0.035-0.04% of P, 18-20% of Cr, 8.5-13% of Ni,0.02-0.05% of Nb, 0.10-0.15% of Al, 0.30-0.45% of Cu, 0.18-0.20% of Ti and the balance of Fe. The stainless-steel and carbon-steel composite plate and the preparation method disclosed by the inventionhave the beneficial effects that the corrosion resistance is good and the phenomenon of intercrystalline corrosion can be effectively reduced.