In consideration of bare optical fiber being fragility, the steel capillary encapsulating technique for FBG sensor was developed in this study, and then the temperature and strain sensing properties of the encapsulated FBG sensor were experimentally studied on material test system and under hot water, respectively. The comparison of the experimental results between encapsulated fiber and bare fiber indicated that the strain sensing properties of the encapsulated FBG sensor are nearly the same as that of bare FBG, however, the temperature sensing ability of encapsulated FBG sensor is improved and the sensitivity coefficient is 2.5 times as much as that of bare FBG. The strain and temperature sensing precisions of the encapsulated FBG are 1 με and 0.05℃, respectively. The encapsulated FBG is proper for application in civil engineering.