The invention discloses a fire detection system amplifier cabinet. Three layers of back plate clamps in an original coal fire detector amplifier cabinet are rearranged, and three layers of fire detector amplifier clamps are arranged into a coal pulverizer first corner fire detector, a coal pulverizer second corner fire detector and a coal pulverizer third corner fire detector which each comprise six coal fire detector amplifier clamps; and an AB oil fire detector, a CD oil fire detector and an EF oil fire detector in an oil fire detector amplifier cabinet are not changed, a fire detector back plate is added into the oil fire detector amplifier cabinet, and a coal pulverizer fourth corner fire detector is arranged on the newly added fire detector back plate. The fire detection system amplifier cabinet has the advantages that an amplifier clamp frame is added into the original oil fire detector amplifier cabinet, the fire detectors of six coal pulverizers are completely independent, the six coal pulverizers only lose the fire detector at one corner if any one clamp frame is de-energized, pulverizer shutdown cannot be caused, and the influence of fire detection system faults on the operation safety of a boiler is reduced.