Porous silica fibers were fabricated aiming to broaden the applications of SiO2 nanosphere materials. The fibers were built with SiO2 nanospheres via electrospinning and calcinations. At first, SiO2 nanospheres (synthesized by Stober method) were surface-modified using.-aminopropyltriethoxysilane to obtain SiO2-NH2 nanospheres, which dispersed homogeneously in the solvent. Then, polyacrylonitrile (PAN) and polymethylmethacrylate (PMMA) were introduced in different weight ratios into the suspension. Subsequently, PAN/PMMA/SiO2 composites were electrospun, followed by preoxidization and calcination to transfer PAN into carbon form and to remove PMMA component. Thus, porous silica fibers were fabricated with SiO2 nanospheres binding together during carbonization and porous structure was formed. The porosity, pore size and pore volume of porous silica fibers were controllable by adjusting the content of SiO2 nanospheres and the weight ratio of PAN/PMMA. Accordingly, the drug adsorption and release performance of these porous silica fibers depended on their microstructural features. The thus-obtained porous silica fibers displayed great potentials in applications such as drug carriers and adsorbents. [GRAPHICS] .