A self-sensing steel strand is designed, which is set a spiral and slant groove on the steel strand center wire and embedded with fiber Bragg grating (FBG) sensor. Hence, the problems of lack of installation space, fragile broken which leads to low survival rate and insufficient monitoring range can be solved. The monitoring strain of FBG sensor with groove and the strain of steel strand are analyzed theoretically. According to the theory of shear lag model of composite material, the relationship between both strains is established. A series of self-sensing steel strand are developed with different helix angle, and the tensile experiments are carried out to determine the variation of the measurement range of FBG sensor. The experimental results show that this method can effectively improve the monitoring range of FBG sensor, When the tilt angle is 30°, the strain range that can be monitored is increased by 44% compared with 0°. Owing to this technique, the prestressing tensioning construction and service of a prestressed box beam of a highway are monitored in real time by using FBG sensor, the survival rate of the sensor is 100%. The strain relationship determined by theoretical and calibration test is compared with the data of the construction tensioning and the secondary tensioning on site, and the errors are less than 5%. This technology achieve the purpose of the whole lifecycle monitoring of the internal prestressed steel strand during construction and service.