Abstract: Aiming at the space environment with widespread high temperature difference and ultra-low temperature, it is important to understand the thermal strain stability of spacecraft materials and structures for ensuring the reliability of simulated ground-based space environmental tests. Brillouin optical time domain analysis (BOTDA) technology can simultaneously detect temperature and strain, and has the advantages of high precision, long sensing distance, anti-electromagnetic interference and low cost. However, it is unknown whether the optical fiber as a sensing element can adapt to the cold and black space environment. In this paper, the Brillouin gain spectra (BGS) of two typical standard single-mode optical fibers at ultra-low temperature were firstly obtained by BOTDA demodulator. Then, the ultra-low temperature performance of the optical fibers was analyzed through experimental data. Finally, the temperature and strain coefficient of the two optical fibers were calibrated. The results show that the tested optical fibers can still form a Lorentz shaped BGS at ultra-low temperature, and the actual frequency shift is consistent with the theoretical frequency shift corresponding to the low temperature, which meets the temperature measurement range requirements of BOTDA sensor in the ultra-low temperature space environment.