The invention belongs to the pneumatic technology field, and relates to pneumatic artificial muscle. The artificial muscle consists of an outer mesh grid, an inner expansion tube, a sealing component and a sealing component with air vents. The outer mesh grid is aligned with the inner expansion tube at two ends and sleeved on the inner expansion tube, with the original length thereof a little longer than that of the inner expansion tube; and one end of the outer mesh grid is inserted into the sealing component, and the other end thereof is inserted into the sealing component with air vents. The inner expansion tube of the pneumatic artificial muscle is inflated with air with a certain pressure, so that the inner expansion deforms to cause the outer mesh grid to expand in the radial direction, so as to enable the pneumatic artificial muscle to expand in the radial direction, contract in the axial direction and output certain tensile force. The pneumatic artificial muscle has the characteristics of compact structure, simple manufacture, low price, high flexibility, high ratio of output force to dead weight, effective energy conservation, automatic buffer, pollution resistance, etc., and can be widely applied to the fields of robots, auxiliary medical apparatus and instruments, aviation, defense industry, etc.