Zinc oxide (ZnO) nanofibers doped with manganese (Mn) are synthesized by electrospinning followed by calcinations at 580°C for 150min. The structure, morphology and element-composition are investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results show that the diameters of Mn-doped ZnO nanofibers are from 60nm to 90nm corresponding to the amount of Mn from 0 wt% to 2.0 wt%, respectively. XPS spectrum indicates that Mn2+ ions exist in divalent state. The gas sensing properties are significantly affected by the Mn-doped ZnO nanofibers and the operation temperature. The sensors exhibit excellent sensitivity, practical selectivity and stability to acetone with a fast response and recovery time at 340°C.