In order to monitor the subsidence and deformation of the unconsolidated strata, a monitoring structure with fiber Bragg grating (FBG) sensors embedded in the borehole and the sensing network system are proposed. With the results from laboratory, the 6 nm wavelength bandwidth of the FBG sensors used for rock strata deformation monitoring is presented. By analyzing the signal resolution factor of the multi-point sensor, the maximum practical six-channel multiplexing of the testing system determined by dominated optical source bandwidth has been researched. A distinctive FBG array composed of 18 FBGs based on wavelength division multiplexing/spatial division multiplexing is designed and implemented. Engineering practice shows the double-loop design can improve the survival rate of FBGs in mines.