Based on the theory of fiber Bragg grating sensing, and using a 2 m planestress material model of the simulation experiment, the wavelength shift regulations of fi-ber Bragg gratings under rock settlement deformation conditions were got, which providedreliable basis for the design of the wavelength bandwidth of sensing gratings. The wave-length increase when the rock layers are under tension, and decrease under compression.Compressive strain sensitivity is bigger than tensile strain sensitivity when the load islower. However compressive strain sensitivity is smaller than tensile strain sensitivity whenthe load is higher. Experimental result coincides well with theory. The wavelength band-width of two neighboring fiber Bragg gratings of the gratings used for monitoring the de-formation of rock layer should be no less than 6 nm. An effective new approach for de-tecting the deformation of rock settlement with fiber Bragg gratings is provided.