A shear displacement sensoring device for monitoring rock sliding based on the principle of optical fiber Bragg grating.The displacement sensor was designed by attaching the fiber grating to equal strength cantilevers.Then the sensor was embedded inside a Φ50 polyvinyl chloride (PVC) tube.Three test models were made using Φ75 PVC tube with the Φ50 PVC tube mentioned before in it.Cement mortar was grouted into the gap between the Φ50 and Φ75 PVC tubes as ratio at 1: 1.Indoor shearing tests on the models were carried out.The curve of the relationship between the sliding distance and the grating wavelength shift was also measured.Results show that the sensitivity of this sensor is 0.5 mm and the maximal sliding distance could reach 30 mm while the grating wavelength could shift up to 1200 pm, of which indicates that the sensor could be well applied into sliding displacement measurement which needs a very high sensitivity.It is proved that the features of the fiber Bragg grating (FBG) sensor we designed are more sensitive and reliable, better anti-interference ability and larger measurement range.The structure of the sensor is simple, and it also can realize remote, real-time monitoring.Thus, the sensor can be used for landslide early warning monitoring.