Our designed vaporizer using natural convection in the atmospheric environment in which air is as heat source to heat cryogenic liquid in the heating pipe, makes it into a certain temperature gasification gas which is of high efficiency, environmental protection, a new generation of heat exchanging, energy – saving equipment. The perfect design and strict production control make air vaporizers have sufficient capability. It can also be operated in cold area like in Northeast China. Under certain condition, it can be operated continuously.