Automatic fire extinguishing device for building fire safety

The utility model discloses an automatic fire extinguishing device for building fire safety, which comprises a fire-fighting assembly and a protection assembly, the fire-fighting assembly comprises a fire-fighting box, a fire extinguisher box arranged at the bottom of the fire-fighting box, and a water inlet pipe arranged on one side of the fire-fighting box in a penetrating manner. A large amount of smoke enters a corridor, smoke enters a ventilation groove formed in the top of a fire-fighting box installed in the corridor and then triggers smoke alarm, meanwhile, an external water pump and a water inlet pipe send water into a water pipe, and then the water pipe sends water into an external pipe installed at the top of the fire-fighting box. A plurality of sprayers mounted on the front surface of the external pipe spray water mist outwards to provide a layer of protection for the fire-fighting box, so that the fire-fighting box is prevented from being damaged by external high temperature, and a firefighter c