Disclosed is a testing device for measuring interfacial shear properties between fibers and media, including a main body, which is a rectangular plate-like structure with L-shaped plates provided at the bottom ends of the main body, a connecting rod provided at a top right of the main body, a groove provided at the top of the main body; and four rotating grooves are provided inside the groove. The rotating grooves are cylindrical structures with raised centers at both ends; and a mounting piece is installed above the left end of the main body; a magnet of a displacement micrometer is connected to a tension trolley, a high-definition camera is turned on, weights are added into a loading bucket and the fiber movement is observed until the fiber is pulled out or sliding friction occurs, and then the camera is stopped and accurate data is tested.