Abstract: In the field of monitoring the deformation of surrounding rock of underground caverns, multi-point displacement meters and sliding micrometers lack continuity in the axial deformation and automatic monitoring, cannot be realized. In view of the above problems, a continuous monitoring method is proposed, that is, the fiber Bragg grating displacement sensors are assembled to monitor deformation of the surrounding rock. This method can get the accurate monitoring value at any point of the hole. Because of the high precision of the fiber Bragg grating displacement meter groups, variation of displacement of the surrounding rock is closely related to the excavation of the caverns, and the wholly deformation law is basically consistent with the results of multi-point displacement meters. But the fiber Bragg grating displacement meter groups can monitor the distribution of axial displacement with in any distance of the whole large-scale monitoring line, and the achieved information is much more and more intuitive. The application of fiber Bragg grating displacement meters in the deformation monitoring of geotechnical engineering is of great significance.