Three types of automatic fire alarm systems were chosen to meet the special requirements of different objects. Full-shield infra-red beam smoke detectors were used for klystron gallery where high frequency electromagnetic field and strong radiation interferences exist, the linac tunnel the storage ring hall and the nuclear physics experiment hall. Cable line-type fixed temperature detector which are suitable for the bad environment of both electromagnetic interference and high-humidity were employed in underground cable tunnel. Ionization smoke detectors, combined rate-of-rise and fixed temperature heat detectors were used in computers and common places. The whole fire alarm system consists of four zone fire alarm control units, a central fire alarm control unit, a simulating indicating panel and fire telephone & emergence broadcaster networks.