The invention provides a pneumatic muscle variant stratosphere airship. The pneumatic muscle variant stratosphere airship comprises an outer-layer gasbag, a pressurization pipe structure, a pneumatic muscle and a pneumatic muscle control structure. When lift gas in a variant gasbag inflates with rising of the flight height, the volume of the gasbag is increased under the linkage effect of the internal pressurization pipe structure and a pneumatic muscle device; certain rigidity is ensured while the outline of the gasbag is changed; and when the airship falls, opposite principles are conducted. The volume of the gasbag is small when the airship is in a low attitude, the volume of the gasbag is increased when the airship is in a high attitude, and the windward area is small in the low attitude, so that wind resistance is reduced. The internal pressurization pipe structure is used for supporting the outer-layer gasbag, a small value can be taken from the gasbag differential pressure in the gasbag, and the strength demand for bag cloth materials of the outer-layer gasbag is reduced. Under the same demand, the unit area weight of the outer gasbag materials can be reduced. The overpressure of the gasbag is reduced to 120 Pa from 500 Pa.