The invention discloses an auto-exit gate locking device which comprises locking lugs, locking shafts, locking connecting rods, a transmission shaft, supporting seats, transmission connecting rods and a balance weight, wherein one end of each locking lug is fixed on a gate lock, and the other end of each locking lug is rotationally connected with each locking shaft; the locking shafts are fixedly connected with the transmission shaft through the locking connecting rods; bearings which are in fit connection with the transmission shaft are arranged on the supporting seats; the transmission shaft is fixed on a concrete foundation through the supporting seats; the balance weight is fixedly connected with the transmission shaft through the transmission connecting rods; and the balance weight and the locking lugs are located at two sides of the transmission shaft respectively. The invention further discloses a gate control system. According to the auto-exit gate locking device and the gate control system, on the basis that an existing device is not affected, the automatic exit of the gate lock can be achieved safely and reliably through the lever principle and the locking lugs rotationally connected with the bearings.