Abstract: A novel system of parallel double-ring temperature sensor is designed and numerical simulated, which is based on the relationship between the temperature and the refractive index of polymer. With the output of the simulation spectrum, the conclusion is achieved that the resonance peaks have distinct displacement as the temperature changes, and the higher thermo-optic coefficient of the polymer is, the more obvious resonance peaks shift. When the temperature increases by 1℃, the resonant peaks shift 32nm. The temperature changes can also be calculated with the resonant peak shift, which provide the feasibility to improve the measurement accuracy of temperature.