Abstract: To overcome the difficulty in signal localization of acoustic emission(AE) detection in low temperature, the technology of fiber-optic ring(FOR) AE was introduced in this article. The theoretical model of FOR AE sensor was built by theoretical analysis. The four-channel FOR AE equipment was built base on the theory of Mach-Zehnder interference. The performance of the FOR AE equipment in low temperature was analyzed thought the AE tests of typical titanium cylinder in low temperature. The results demonstrate that the FOR sensor can be directly coupled on the cylinder in low temperature for AE detection, the average signal amplitude can reach 90 dB; The AE signals can be located by using four-channel FOR AE equipment, the signal location deviation will not exceed 8% of the maximum sensor spacing. This will lay a certain foundation for the application of FOR AE detection in engineering.