Micro/nano fiber with subwavelength diameter is a sort of novel optical waveguide, which is neither similar to normal optical fiber, nor to integrated waveguides. In such micro/nano fibers, light transmits along with high ratio of evanescent field, dispersion, evanescent wave coupling, and low bending loss. The ring resonator composed of such micro/nano fiber have characteristics of low loss and high quality factor, so the micro/nano fiber ring resonator as a high-sensitivity optical sensor has larger research value and application prospect in communication and sensing fields. Meanwhile, micro/nano fiber combination with some new materials can reveal more new optical and physical phenomena, and therefore it can provide a new effective way to the study of material properties of optical waveguide devices in microscopic scales (e.g. we first proposed micro fiber gas sensor based on graphene). We have published more than 20 papers about relevant results on IEEE J Sel Top Quantum Electon, Applied Physics Letters, Optics Express, Opt Letters and other top international journals, the number of times cited by others in SCI is nearly 100 times. Four times International Conference Reports, including top international conferences in the field of international optical fiber sensing (OFS) such as oral report and Post-Deadline oral report. The research is also funded by National Natural Science Foundation of Key Projects and Youth Fund Projects.