Abstract: In order to achieve the purpose of high-precision temperature sensing, a novel dual-core photonic crystal fiber coupled perturbation structure was designed. The finite-difference beam propagation method was used to analyze the sensing characteristics of the structure. The Beampronp module of RSOFT software was used to simulate the characteristics of the sensor. The results show that the refractive index sensitivity can reach 7000nm/RUI under the condition of dual core coupling (RUI is the refractive index unit), the coupling spacing sensitivity can reach 2. When the liquid is filled with ethanol, the sensing structure can realize the detection in the temperature range of 278K~338K, and the sensitivity in this range can be up to 4nm/K. The sensor has the characteristics of high linearity and simple process, and the structure is helpful and meaningful to the research of other related sensors.