In order to ensure the safety of constructors and construction machinery in the process of physical excavation and demolition of Dalian Huaneng concrete silo, a long-gauge fiber Bragg grating (FBG) strain sensor was designed to monitor the whole process in real time. Through the static and dynamic analysis of the strain data collected by sensors, the variation of the surface strain and natural frequency of the silo structure with the opening rate was obtained, and then the structural damage was identified. During the monitoring of the concrete silo, the sensor operated steadily, the structural strain response data during the whole demolition process was obtained, and an early warning of structural collapse was given. The concrete silo collapsed successfully according to the predetermined direction. The research results have solved the problems of blindness and passive delay of safety measures in traditional demolition work and provided an important technical reference for similar concrete demolition work.