Abstract: This paper studied an experiment which can manufacture micro-nano optical fiber with the use of hydrofluoric acid, and using OptiFDTD to study its performance. In this experiment, with the use of CCD and data acquisition card for real time monitoring the process of HF etching and recording relationship between diameter of quartz fiber with the change in power loss, we found that the relationship between diameter of quartz fiber with the change in power loss roughly in line with the Boltzmann function model. Through simulating the Poynting vector distribution of micro-nano optical fiber with using OptiFDTD software, it shows that micro-nano optical fiber evanescent field will be bigger and bigger with?the decrease of the micro-nano optical fiber diameter, and when the micro-nano optical fiber diameter compare to the wavelength of incident light, waves almost along the surface of the fiber optic to propagate. As a result, with lots of favorable properties including simple preparation, small dimension,big evanescent field, micro-nano optical fiber shows attractive application prospect in the field of sensor and so on.