At present, the shortage of clean energy liquefied natural gas ( LNG ) provides important development opportunities for coal chemical enterprises. If the methane which is rich in the syngas of coal gasification process is extracted from methanol syngas by cryogenic separation and LNG is produced by liquefaction as clean energy, it not only reduces the power consumption of subsequent syngas compressors, but also has good economic and social benefits. The cryogenic separation technology of synthetic gas and cryogenic was introduced,  and the economic value of the technology was analyzed.