ZnO nanoparticles (ZNPs) were obtained via a direct calcining method. ZnO nanofibers (ZNFs) were fabricated by electrospinning polyacrylonitrile (PAN) and zinc acetate (Zn(Ac)(2)) solution and calcining PAN/Zn(Ac)(2) nanofibers. The samples were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), fourier transform infrared spectrum (FT-IR), X-ray diffraction (XRD), photoluminescence spectra (PL) and UV-vis spectroscopy. The results showed that the sizes of the ZNPs ranged from 90-275 nm with the average value 170 nm. The ZNFs were constructed by a series of nanoparticles along the fiber axis, and the sizes of the nanoparticles ranged from 50-250 nm with the average size 150 nm. The ZNPs and the ZNFs were both crystallized with hexagonal wurtzite structure. Although the nanoparticles in the ZNFs accumulated along the fiber axis and more surface oxygen vacancies were formed for the ZNPs, the distance of photocatalytic activities between these two kinds of catalyst was only 5 %. Besides, both the ZNPs and the ZNFs could be recycled and reused for their stable photocatalytic activities. Compared with the ZNPs, the ZNFs showed a wider application for their fibrious morphology.