Abstract: By using BOTDA distributed optical fiber sensing technology, the ordinary H-pile is transformed into a pile body with a self-sensing ability, so that it can automatically acquire structural health data like strain, bending moment, deflection and so on during excavation process. Through analysis of the forces acting on the H-pile, a method for continuous calculation of bending moment of the piles, which doesn’t need to determine the location of neutral face, is proposed, and it can make temperature compensation. The technology has been applied in a foundation pit, and the a successful application shows that it has good in-situ adaptability. It can be employed to monitor the real-time deformation of the foundation pit. Moreover, it has some advantages like distributed measurement, temperature self-compensation, etc., therefore it can be widely used as a new type of protective structure in foundation pits.