The invention discloses a system for co-producing mixed olefin, arene and liquefied gas from crude dimethyl ether. The system is characterized by comprising a heat exchanger, an electric heater and a degradation reactor in series connection, wherein the bottom of the degradation reactor is connected with the bottom of the heat exchanger; the top of the heat exchanger is in sequential series connection with a waste heat boiler, a water cooler, a washing tower, a compressor, an oil-gas separator and a de-hydrocarbon tower; the bottoms of the oil-gas separator and de-hydrocarbon tower are both connected with a stabilization tower; and the bottom of the stabilization tower is in series connection with an absorption tower. According to the system disclosed by the invention, by making full use of the energy and remaining effective raw materials in dimethyl ether production and comprehensively developing multiple new types of products, the petroleum resource is replaced, the industry chain is lengthened, and thus th
