The present invention is to provide a building intercom alarm system which is characterized in that the building intercom alarm system comprises intercom devices, alarm buttons, alarm input wires, processors, first decoders, microphones, loudspeakers, cameras, indoor units, floor distributors, connection network cables, a network switch, a center management main machine, a monitoring server, a second decoder, an alarm device, a visual intercom and doorway management machines. Each indoor unit is internally provided with the intercom device; the lower end of each intercom device is provided with the processor; the intercom device is electrically connected with the processor; the lower end of each processor is provided with the first decoder; and the processors are electrically connected with the first decoders respectively. The beneficial effects of the building intercom alarm system are that the system can be in wired or wireless communication with a residence community property management center or community guards through the center management main machine, thereby achieving the safety protection functions of preventing thefts, disasters and coal gas leakage and the like, and providing maximum guarantee for life and property safety of a house owner.