Aiming at the low-speed impact load localization and vibration testing requirements of aerospace composite flexible structure, The Fiber Bragg Grating sensor network monitoring system is established. The increasing sampling technique is used to process the impact response signal, then the generalized cross-correlation delay estimation method is used to extract the time difference relationship between the sensor response signals. On this basis, the rapid identification of the impact position of the composite flexible structure is realized by considering the position information of the sensor comprehensively. The experimental results show that the area of six impact sample points and the specific coordinates of the location can be accurately identify respectively by this method. The average error of the coordinate positioning is about 3cm. The self-vibration mode and the natural frequency of the composite structure are achieved by using Fiber Bragg Grating sensor network monitoring system simultaneously. The finite element model of the composite structure with triangular section is established by using Patran. The natural frequency of the simulation is in good agreement with the experimental result, which proves that the Fiber Bragg Grating sensor has good vibration test performance.