A 128°YX-cut lithium niobate (LiNbO₃) delay-line-type surface acoustic wave (SAW) temperature sensor with a dual-electrode interdigitated transducer (IDT) was designed to meet the demand for temperature measurements in low-temperature, harsh environments. A temperature-sensor model was built using COMSOL software, and the optimal model parameters were determined. The sensor was tested within a temperature range of -196 ℃ to 100 ℃. According to the simulation results, the electromechanical coupling coefficient of the sensor with the dual-electrode finger structure was 5.35%. Moreover, the sensor’s resonance frequency exhibits a strong linear relationship with temperature, with a temperature sensitivity of 26.2 kHz/℃ and a frequency temperature coefficient of -83.4×10^-6/℃, demonstrating the reliability of LiNbO₃ in low-temperature environments.