Polarization-maintaining micro/nanofibers have various applications in fields including optical communication, sensors, nonlinear optics, and quantum optics. Temperature stability is a key factor in the numerous applications of such fibers. Herein, the temperature characteristics of birefringence of polarization-maintaining micro/nanofibers are studied through experiments and software analysis. By using the polarization interference method, a blue-shift interference spectrum can be obtained with the increase of the temperature. The relationship between temperature and birefringence is obtained. The experimental results show that the influence of temperature on polarization-maintaining micro/nanofibers is much less than that on ordinary polarization-maintaining fibers. The measured results are consistent with the theoretical results.