The utility model discloses a producing device for composite steel plate, which comprises a blank conveying mechanism, a rolling mill, a pinch roll and a coiling machine connected sequentially and correspondingly, as well as a hot straightening machine, a cooling table and a shear line connected with the rolling mill sequentially. Partial or all equipment such as water cooling equipment, a multiple length shearing machine, a checking rack, a plate turnover machine, an inspection equipment, a paint and punch marking machine and a chopping board rack, as well as other relevant matched auxiliary equipment also can be additionally arranged on the producing device. The device not only can produce steel coil with breadth ranging from 300 to 3800mm, but also can produce plate of moderate thickness with thickness ranging from 4 to 60mm and breadth ranging from 300 to 3800mm. The producing device has the characteristics of saving energy, improving product rate and lengthening the steel plate length. By producing the medium plate with the same specification, the utility model has the advantages of low production cost, great market capacity and strong product competitiveness as compared with other devices. By adopting the utility model, the production cost of the medium plate can be reduced, the added value of enterprise steel coil product can be improved, and the production flexibility as well as the equipment operation rate can be improved.