LNG refers to liquefied natural gas. It is a kind of colorless, odorless and non-toxic liquid obtained by separation and removal of liquid, pretreatment (desulfurization, decarburization, dehydration and mercury removal) and low-temperature condensation processing of na-tural gas at portal so that the main component methane ( CH4) of natural gas is liquefied at ultra-low tempera-ture (-162 ° C) under atm-ospheric pressure. LNG volume is approximately 1/600 of gas volume before liquefaction so that it is very easy for transportation. Its main component is methane, usually accounting for above 90%. At atmospheric pressure the boiling point is about -162 ° C, density is about 0.425kg/L, and its volume is about 1/625 of that of the same amount of gaseous natural gas. Compared with ordinary commercial natural gas, LNG contains more methane and less impurity so LNG is cleaner, more environmentally friendly and more efficient (high heat value). High pure LNG for vehicle fuel will fully burn so as to fully play the automobile engine performance and realize more envir-onmentally-friendly emission.