Abstract: Disclosed is an inclinometer system capable of detecting the inclination of the ground using a fiber bragg grating sensor to precisely measure the deformation of the ground. The inclinometer system includes at least one measuring unit, and the measuring unit includes a body provided therein with a receiving part, a frame inserted into the body, a weight member inserted in to the frame and having one end hinged to the frame, the weight member rotating in cooperation to inclination of the body, an optical fiber 5 passing through both the body and the frame such that one end of the optical fiber is fixed to the weight member, a fixing member installed into the frame to fix an opposite end of the optical fiber, and a fiber bragg grating (FBG) sensor attached to the optical fiber.