Aimed at the important indicator of deep displacement in landslide body，based on the optical time domain reflection technique, a composite optical fiber transducer was designed to monitor the deep shear displacement. The transducer is composed of square PVC pipe，capillary pipe，optical fiber and mortar. Firstly, the surrounding of 40 mm×40 mm×500 mm (2.0 mm thick) PVC tube was grooved, and the Φ1×500 mm steel capillary was placed in the guide groove. Then the fiber was used to penetrate capillary tube. One end of the optical fiber was fixed，and the other end was wound into a bow form. At last, the mortar with diameter of 110 mm was poured outside PVC, so that a cylindrical composite optical fiber transducer was fabricated. The slope model shear test experiment shows the transducer detection accuracy is 1 mm and the maximum measurement range of fiber grating is 40 mm. Study shows that the composite optical fiber transducer has the advantages of high sensitivity，wide measuring range and convenient installation, and can be used for in-situ landslide monitoring and geotechnical engineering structure monitoring effectively.