The utility model relates to a semiconductor control rectifier (SCR) postprocessor with a combined structure, which is characterized in that foam metal carrier structure units are arranged at the front end and at the rear end of an SCR main carrier catalytic agent respectively, the interval between a front foam metal carrier structure unit and the SCR main carrier catalytic agent is 50-200mm, and the interval between a rear foam metal carrier structure unit and the SCR main carrier catalytic agent is 20-100mm. Two foam metal carrier structure units are fixed through metal supporting plates made of stainless steel, metal supporting sheets and fixing bolts, wherein the metal supporting sheets are in zigzag shapes, one ends of the metal supporting sheets are welded onto the metal supporting plates, and the other ends of the metal supporting sheets are fixed with the foam metal carrier structure units through the fixing bolts. Each foam metal carrier structure unit has the mesh number of 5-50ppi, the thickness of 20-35mm and the diameter of 60-90mm larger than that of a hole of the supporting plate. The foam metal carrier structure units coated with catalytic agents are arranged at the front end and at the rear end of the SCR main carrier catalytic agent respectively, thereby improving urea decomposition effects and proportion of NO2, improving NOX removal efficiency of NH3, reducing overflow amount of the NH3 and reducing secondary pollution. The SCR postprocessor with the combined structure is simple and convenient in producing technology, high in efficiency, low in cost and suitable for a postprocessing system of an automobile with excessive 4-country emission standards.