In this paper, a highly sensitive optical fiber temperature-sensing probe is prepared by integrating the conical polymer waveguide with an optical fiber using simple dipping and ultraviolet curing techniques. The experimental results show that the temperature sensitivity of the structure at low temperatures is 123.6 pm/°C, and the sensitivity observes a nonlinear increasing trend with an increase in temperature. Among them, the polymer waveguide has a compact structure, with an axial dimension of 300 μm and a minimum radial dimension of 2 μm. This prepared probe based on the waveguide has good temperature response characteristics and biocompatibility. It can also realize point detection and has significant application prospects in the field of biomedicine.