Fire alarm system in building

The invention discloses a fire alarm system in a building, which comprises an active alarm module and a passive detection module connected with a local server. The local server is in signal connection with a background cloud server, the active alarm module adopts manual operation to give an alarm, the passive detection module comprises a plurality of slave computers distributed in the building, the slave computer is provided with an equipment group and a wireless communication module, and the equipment group establishes signal connection with the local server through the wireless communication module. According to the system, a plurality of slave computers with equipment operation feedback modules are arranged, fire information obtained by the slave computers is fed back through wireless communication modules, fire alarm work is carried out in time, equipment in an equipment group can be monitored in real time through the equipment operation feedback modules, and when the equipment in the equipment group is f