In order to solve the problem that the traditional piezoelectric (PZT) sensor can not be implanted into the ammunition to monitor the polymer bonded explosives (PBX) damage, a PBX acoustic emission monitoring system based on the micro-sensor of the fiber Bragg grating (FBG) was constructed by using a tunable narrowband laser source. The uniaxial tension, compression and pencil lead break experiments of the PBX materials were carried out, and the signal characteristics monitored by the FBG and PZT sensors were compared. At the same time, the environmental adaptability and signal direction sensitivity of the FBG method were also studied to verify the basic performance of the monitoring system. The results show that: although the amplitude of the signal monitored by FBG in the test is slightly lower than the PZT, it can also generate output signal above the millivolt level, which can be applied to online monitoring of PBX damage; When the ambient temperature and strain field are less than ±3 ℃ or ±25 με, respectively, the FBG-AE system can effectively monitor the AE signal generated by PBX damage; FBG is sensitive to the direction of AE signal, and the signal amplitude is the lowest in the 90° and 270° directions (the direction of perpendicular to the FBG axial). It is proposed and verified that the gluing method of bending FBG can reduce the difference in the sensitivity of the FBG in response to AE signal, which is beneficial to improve the positioning accuracy of the acoustic emission source.