A temperature sensor based on the principle of optical interference is proposed. A Gaussian beam is generated by introducing a single-mode fiber in the reference optical path, and the fiber Bragg grating structure is introduced into the measurement optical path. Parallel Gaussian beams are generated by incident light passing through the fiber Bragg grating and collimator. The Laguerre-Gaussian beams with orbital angular momentum are generated through a spiral phase plate. The two beams of light are interfered on the beam combiner, and the spiral interference image is generated. The fiber Bragg grating structure is introduced into the measurement optical path, which mainly uses the optical delay characteristic of fiber Bragg grating. The phase delay of light propagation is generated in the fiber Bragg grating when the ambient temperature changes. The phase difference between the measurement optical path and the reference optical path is changed, resulting in rotation of the spiral interference image. The interference image is detected in real time by a high-resolution camera. Image processing of interference image is executed to extract the change information of interference image accurately. The temperature sensitivity of the sensor reaches 4.08 °/℃ by the above method, which will have important application value in the field of temperature sensing.