The invention discloses a sliding type steel-plate-pressing bending mechanism. The sliding type steel-plate-pressing bending mechanism comprises a frame; an accommodating groove is formed in the middle part of a top plate of the frame; a lifting through groove is formed in the bottom surface of the left side of the accommodating groove; a push oil cylinder is fixedly arranged at the bottom surface of the top plate of the frame; a lifting plate is fixedly arranged on a push rod of the push oil cylinder; the lifting plate is inserted into the lifting through groove; a mobile plate fixing groove body is fixedly arranged on the top plate of the frame; the left end of the mobile plate fixing groove body is positioned at the right end of the lifting through groove; a mobile pressing plate is inserted into the mobile plate fixing groove body; the right end of the mobile plate fixing groove body is fixedly arranged on a connecting plate body which is fixed on the right end of the right plate of the frame; a mobile oil cylinder is fixedly arranged at the right end of the connecting plate body; a push rod of the mobile oil cylinder penetrates through the connecting plate body and extends into the mobile plate fixing groove body. The bending mechanism disclosed by the invention is capable of detecting the bending height of a thin steel plate when being used for bending the thin steel plate, so that the bending satisfies the requirements; by adopting automatic bending, no manual bending is needed, so the production efficiency is greatly improved.