In order to solve the needs of shape perception when robots interact with the outside world,this paper proposes a method based on FBG to solve the shape perception of robot tentacles.The fiber Bragg grating is implanted into the flexible silica gel sheet in the form of no binder and fixed.When the flexible silica gel sheet sticks to the surface of the measured object,the shape change of the silica gel sheet will drive the shape change of the implanted fiber.Based on the relationship between wavelength drift and bending curvature of fiber,the surface shape of the measured object is constructed by combining the surface reconstruction algorithm,and the sensitivity of the flexible sensor is analyzed.The experiment proved the feasibility and stability of the shape sensing system,with a sensitivity of 65.822 PM/m-1,a spatial resolution of 3cm and a measurement error of about 2.9 %.The sensor has simple structure and good anti-interference performance,and its sensitivity and spatial resolution can be adjusted to adapt to different situations by changing the depth of fiber implantation and the distance between gratings,providing a reference for implementing the shape perception of robot tentacles.