The invention relates to a gas storage cabinet for storing biogas and exhausting gas to outside under constant pressure. The gas storage cabinet comprises a bottom part, an outer shell, a gas storage capsule, and a pressurizing device, wherein the outer shell is arranged on the bottom of the gas storage cabinet; the outer shell comprises a top part and surrounding parts; the gas storage capsule comprises a plurality of overlapped flexible bag cavities, and fluid between the adjacent bag cavities flows through one other; the capsule cavity at the bottom of the plurality of capsule cavities is provided with at least two joints; a gas inlet pipe, a gas outlet pipe and a water discharging pipe are communicated with the fluid in the gas capsule through the at least two joints; and the pressurizing device is arranged above the gas storage capsule and applies pressure to the gas storage capsule to obtain gas output pressure.