The invention relates to a preparation method of a stainless steel-carbon steel composite board, which belongs to the technical field of material and comprises the following steps: (1) removing and cleaning rusted layers and oxidative layers of stainless steel board material and carbon steel board material; (2) alternately stacking the stainless steel board material and the carbon steel board material; (3) arranging a composite blank between two metal panels to constitute a clamped composite blank, or welding two composite blanks together by electric welding to constitute a combined structure of the composite blank, a blocker and the composite blank, and arranging the combined structure between two metal panels to constitute a clamped composite blank; (4) welding the peripheries of contact surfaces of two adjacent steel boards under a vacuum condition; (5) arranging the composite board in a resistor furnace for heating and heat preservation; and (6) rolling the composite board by a rolling mill. The method disclosed by the invention prolongs the service life and enlarges the application scope of the stainless steel-carbon steel composite board. Compared with an explosive compounding method, the method causes small environmental pollution, and has low requirements on the production environment, in addition, the shape of the board is flat, and the product yield is high.