A large-span enclosed structure is supported by a monolithic membrane cloth joined together by air pressure， the lower edge of the space is tightly fixed on the ground or flat wall, and is anchored by metal components and concrete beams, continuously inflating into it, It expands the whole membrane like a balloon, forming a fixed air support due to the pressure difference between the inside and outside of the membrane. Equipped with advanced automatic control system, automatic balancing inflatable equipment and generator which can start automatically when power failure, it can keep the gas film in normal use for a long time, and can be in the state of unmanned automatic control for a long time.