Abstract: The operating principle of the cryogenic liquid(liquid nitr ogen,liquid argon and liquid oxygen)air-supply systetn has been introduced in this paper,The advantage of storage and transport.cryogenic liquid tank,evaporatorand air-supply systeln have been described. The storage and transport of cryogenic liquid have several advantages such as high efficiencv,stable pressure,low cost,safe use and quick,simple air-supply etc,This svstem can be used in electronic industry and machining which use a great quantity of highly pure nitrogen,argon as protective gases.After evaporation of liquid oxygen,the air-supply system will offer pure oxygen without any pollution。Instead of industry oxygen bottle and provide patients with clean respiratory oxygen.