Abstract: An automatic fire door closing device includes a hydraulic main engine, an arm rod, a rotating shaft, a connecting plate and a clamping device, and further comprises a fire monitoring and response device and a driving device. The driving device includes a linkage rod rotatably connected to the connecting plate, a transmission column rotatably connected to the connecting plate, and a transmission rod fixedly connected to the transmission column, one end of the linkage rod has a hook part for hooking the transmission rod, and the transmission column cooperates with the clamping device, when smoke or open fire is monitored, the hook part of the linkage rod is disengaged from the transmission rod, and the rotation of the transmission column makes the clamping device to release the rotating shaft. The device reduces cost with simple structure, high integration and low installation difficulty.