The invention relates to a composite steel plate. The composite steel plate is characterized by at least comprising an upper layer plate, an interlayer and a lower layer plate, wherein the upper layer plate can be a steel plate or a glass plate, if the upper layer plate is a steel plate, one or more peak parts can be arranged on the steel plate; the interlayer is produced by glass foaming or made of foamed glass and combined by a plurality of units, and a plurality of empty grooves are formed in the interlayer, thereby having the effect of saving material and simultaneously achieving the effects of heat insulation and flame resistance; the lower layer plate can be arranged or not necessary to arrange, if the lower layer plate is arranged, the lower layer plate can be a steel plate or a glass plate, if the lower layer plate is a steel plate, one or more small peak parts can be arranged on the steel plate, or the lower layer plate can be shaped into a flat plate; and gluing material can be coated on the lower side of the upper layer plate or the upper side of the interlayer to combine the upper layer plate or the interlayer into a whole; if the lower layer plate is arranged, the gluing material can be simultaneously coated on the upper side of the lower layer plate or the lower side of the interlayer during the step of coating the gluing material so as to combine the lower layer plate or the interlayer into a whole; therefore, the composite steel plate which is combined by the upper layer plate and the interlayer and has fire resistance and flame resistance is generated; or the composite steel plate with the fire resistance and the flame resistance is formed by combining the upper layer plate, the interlayer and the lower layer plate.