Because of the high cost and inconvenience caused by the need for a particular pump laser or heating resistor for the optical fiber thermal anemometer, a high-sensitivity optical fiber thermal anemometer based on the heating effect of the light source is proposed. First, the Fabry-Perot interferometer is made with ultraviolet curing glue on the end face of single-mode optical fiber and used as a sensing probe. Then, a higher initial temperature is obtained by using the heat absorbed by the sensor probe to the input broadband light source. Finally, the wavelength drift of the interference spectrum caused by the temperature drop and strain of the sensor probe under the action of air flow is measured, and the wind speed measurement is realized according to the specific relationship between the wavelength drift and the wind speed. The sensor is measured in the wind speed range from 0 to 7 m/s. The results show that the sensor achieves wind speed sensitivity up to -3.13 nm/(m·s ^-1), and the response time is about 250 ms.