Promoting the multifunctional development of a single sensor is one of the new research hotspots in the field of structural engineering monitoring technology. In this paper, ABAQUS modal analysis, artificial excitation test and bending test are carried out on reinforced concrete beams with steel bars embedded with fiber bragg grating (FBG) strain sensors to explore the feasibility of the FBG strain sensor embedded in the steel bar to monitor the natural frequency of the reinforced concrete beam in the unloaded and damaged state.The results show that the natural frequency of the unloaded test beam obtained by the artificial excitation test is about 37.43 Hz, which is compared with the ABAQUS finite element modal analysis result of 38.366 Hz and the theoretical calculation result of the first-order natural frequency of the test beam lateral vibration. 36.167Hz is basically the same, and the error does not exceed 2.5%; In the flexural test, the FBG strain sensor can still stably monitor the natural frequency of the