The invention relates to the field of application of fiber gratings, and discloses a fiber grating sensor. The fiber grating sensor comprises a fiber (1), a shell (2) and clamping pieces arranged in the shell (2), wherein the clamping piece is provided with an accommodating channel (3) for enabling the fiber (1) to pass through; the clamping piece comprises a pressing part (4) for pressing the fiber (1) and a convex edge part (5) connected with the pressing part (4); the convex edge part (5) is clamped in the shell (2); the convex edge parts (5) of the two clamping pieces are arranged oppositely and a gap is left between the convex edge parts of the two clamping pieces; and the part, located between the pressing parts (4) of the two clamping pieces, of the fiber (1) is provided with a grating. The fiber grating sensor provided in the invention is bonded with no need of a polymeric material and has good reliability and practicability.