A fully-automatic double-direction cylinder comprises a cylinder body, a piston, a piston rod, an air inlet and outlet passage in the piston rod, an air inlet switch and an air outlet switch, wherein the air inlet switch and the air outlet switch are arranged in the piston. The fully-automatic double-direction cylinder is characterized in that when the piston moves, the air inlet switch and the air outlet switch are driven to move, and the air inlet switch and the air outlet switch touch a cylinder wall when approaching stop points, consequently, the position of the air inlet switch and the position of the air outlet switch are converted, and the positions are maintained unchanged under the pressure difference of the two sides of the piston until next touch. Consequently, the air inlet switch and the air outlet switch are automatically controlled to change air inlet and air outlet in the cylinder, so that the fully-automatic double-direction cylinder is made to operate automatically.