Abstract: This paper reported a new kind of micro fiber ring resonator (MFR) temperature sensor. Due to its sub-wavelength diameter, the micro fiber ring resonator has a high Q factor, and hence it can be used for high-precision optical sensing and measurement. The refractive index of the MFR varies with temperature, which can be detected by measuring its change in optical spectrum. Experimental results show that the temperature sensitivity of the MNFR is~19 pm/℃ within 20℃~30℃. Such a type of MFR temperature sensors has the advantages of very simple fabrication, extremely small size, quite low cost, and easy to be integrated, et al.