A cryogenic temperature sensor based on the temperature dependence of stable color centers in a commercial single-mode optical fiber is proposed. The radiation induced attenuation spectra at different temperatures are measured and decomposed by Ge-NBOHC and Ge(X) color centers. The configurational coordinate model is used to explain the temperature properties of the color centers. A series of experiments are conducted to evaluate its performance in the temperature range from 10°C to -196°C, and the results suggest that the temperature sensitivity is ∼0.17 dB/km/°C with a resolution of 0.034°C, and the nonlinearity and repeatability error are ±3.8% and 1.4%, respectively.