Fiber Bragg grating(FBG) strain sensors were characterized and embedded into the pre-stressed concrete beam of HuLan river bridge.Embedding techniques and protective methods suitable for civil engineering were presented.With FBG sensors,internal strains of the concrete beam were determined during the stressing process.FBG sensors show the advantages of strong surviving capability,absolute value measurement and long service life over conventional electrical strain gauge in experiments.The results indicate that it is possible to establish a structural health monitoring system based on fiber optic sensors.