The invention discloses a self-weight separation automatic discharging device of a tunnel kiln. Sintered bowl bases out of the tunnel kiln are arranged in a stripping body, the stripping body and the sintered bowl bases are carried in grooves formed in an overturn plate, the overturn plate rotates around an overturn motor to rotate the stripping body and the bowl bases by 180 degrees and is fastened on a sliding rail of a separation table in an upturned mode, a piston rod of a moving air cylinder is pushed out to enable a moving plate to push the stripping body and the bowl bases to move along the separation table sliding rail, when the stripping body and the bowl bases move to the other end of the separation table and are clamped into the upper portions of two levels of circular holes formed in the separation table, due to the fact that the diameter of the bowl bases is smaller than the inner diameter of the two levels of circular holes, the bowl bases fall onto the upper portion of a third conveying belt under the action of gravity, the stripping body is carried to the upper portion of a first conveying belt by a separation pneumatic claw, and therefore the separation work of the whole stripping body and the bowl bases is completed. The self-weight separation automatic discharging device of the tunnel kiln solves the problems that traditional equipment is large in labor intensity, poor in working environment and low in automation degree, and has the advantages of being simple in operation and reducing working faults.