The problems related to concrete structure maintenance can be indicated as unavailableness of (i) precise and economical monitoring system and (ii) safe and durable repair and retrofit engineering construction method. In recent years, early-strength, freezing-thawingt-resistance, high-durable and easy thickly-spray shotcrete has been developed. In this research, optical fiber sensory technology was utilized to monitor the deformational properties of shotcrete-retrofitted RC beams. Previously, the reliability and stability of the optical fiber sensory system has been verified by examining the steel expansion coefficient of a steel plate. By investigating crack propagation characteristic, it is confirmed that thefiber sensory technology can be applied to grasp the deformational behavior of retrofitted RC structures.