LNG is the abbreviation of liquefied natural gas, the major component is methane, which mainly used in the peak load and accident peak of the gas supply in urban pipe network, electricity generation, living gas in small and medium-sized cities and towns, automotive fuel, industrial fuel, chemical gas, etc.. Before the processing and transportation to the end user of the LNG, the feed gas pretreatment of the LNG shall be performed, the important link during the pretreatment is the desulfurization of the feed gas. The natural gas often contains the acid gases such as hydrogen sulfide and carbon dioxide, and the hazardous materials such as mercaptan, carbon sulphide and sulfur dioxide, among them, the acid gas, especially the hydrogen sulfide, has the maximum harm, and the gas containing sulphur compound would accelerate the corrosion of metal pipe and equipment and shorten its service life, and the hydrogen sulfide is extremely toxic, if the feed gas has been leaked, both personal safety and environment will be threatened, the natural gas with high hydrogen sulfide can come out  peculiar smell at burning, and cause catalyst poisoning during catalytic processing, polluting the environment, reducing the reactant productivity, increasing the cost and declining the economic benefit. Therefore performing pretreatment to the LNG feed gas is a very important link.