The invention discloses a fully-sealed anaerobic tank with an impact-type feeding system. The fully-sealed anaerobic tank comprises an anaerobic tank body, a feeding port, the impact-type feeding system, a water pressing tank, a discharging port, a gas guide pipe, a switch, a gas-water separator, a three-way joint, a gas storage bag, a purifying adjuster, a pressurizing pump and a special cooker, the anaerobic tank body is placed on the ground, the impact-type feeding system is connected with the anaerobic tank body through the feeding port and positioned at the left end of the same, the water pressing tank is connected with the anaerobic tank body through the discharging port and positioned at the right end of the anaerobic tank body, the gas guide pipe is connected on the left upper portion of the anaerobic tank body through a thread, the switch is mounted at a second section of the gas guide pipe, the gas-water separator is mounted on the gas guide pipe in rear of the switch, the three-way joint is mounted at a fourth section of the gas guide pipe, a single vertical outlet of the three-way joint is connected with the gas storage bag through the gas guide pipe while another outlet of the same is connected with the purifying adjuster through the gas guide pipe, the pressurizing pump is mounted on the gas guide pipe in rear of the purifying adjuster, and the special gas cooker is positioned at the tail end of the gas guide pipe.