The utility model discloses a nuclear power station fire alarm monitored control system, the system is including the nuclear island fire alarm host computer that connects gradually and conventional island fire alarm host computer, first gateway and second gateway, communication device, switch, host computer. Nuclear island fire alarm host computer, conventional island fire alarm host computer, first gateway reaches the second gateway constitutes the C -BUS looped netowrk jointly. The system still include through the bolt fastening in the regional reserve fire alarm dish in top of host computer, reserve fire alarm dish is connected first gateway reaches between the second gateway for the collection is through the regional fire alarm data of the nuclear power of C -BUS looped netowrk transmission and show the regional fire alarm data of nuclear power. The utility model discloses nuclear power station fire alarm monitored control system can the unable normal during operation of host computer, through reserve fire alarm dish shows nuclear power station fire alarm data to nuclear power station managers knows the regional conflagration particular case of nuclear power, in time takes the fire protection, prevents the fire spreading or the condition out of control.