The health of bearing has a tremendous influence on rotating machinery. A failing bearing not only could jeopardize the safety of flight but also induce collateral damages. It is necessary to monitor and judge the tiny earlier fault in an effective way. Compared with the conventional vibration detection approach, acoustic emission (AE) can detect the earlier state of the fault, as well as can diagnose the fault type and damage grade. The principle of rolling bearing fault by AE detection and the novel AE detection technique using fiber Bragg grating (FBG) are introduced. A comparative experimental study on the use of FBG sensor and the commercial PZT based transducers AE analysis for defect identification of the seeded defect on the outer race of the test rolling bearing was carried out. The experimental and analyzed results show that the signal of the FBG has better spectra than the PZT with clearer lines and lower noise basis. The fault frequency and damage degree can then be more easily identified. Finally, the applications of this technique in helicopter maintenance are introduced.