Utilizing fiber Bragg grating to detect high-frequency，small-energy ultrasonic guided waves containing damage information is one of the key technologies and development directions for structural health monitoring. Firstly，the ultrasonic detection principle of fiber Bragg grating and a special phased-shifted fiber Bragg grating with high sensitivity and broad bandwidth is introduced， and the directional sensitivity and the installation methods of the grating are discussed. Secondly， the broadband light source demodulation method and the tunable laser demodulation method to convert the high-speed and small-amplitude Bragg wavelength shift into voltage output are presented and compared. Then，typical and important applications on aerospace composite structures，including impact monitoring， acoustic emission monitoring and acousto-ultrasonic monitoring， are referred to as examples to discuss the research progress of damage determination，localization， classification and other health monitoring. Finally， the application of fiber Bragg grating in ultrasonic structural health monitoring is summarized and prospected.