Abstract: Taking E glass fiber as raw material, the acid leaching process was used to preare high silica micro-fiber, the effects of different mixing forms and stir rates on SiO2 content and macrograph of the fiber were studied. The results show that raising mixing rate appropriately could make dispersion accelerating, but the too high mixing rate not only reduced SiO2 content, but also seriously affected the length of the fiber. Under the condition of double-directional mixing and stirring rate of 75 r·min-1, the high silica micro-fibre with SiO2 content of 97.38wt% could be obtained, and the specific surface area and average aperture of the fiber were 364.59 m2·g-1 and 0.73 nm, respectively.