Long ZnO nanofibers have been fabricated by a PVP assisted electrospinning technique using zinc acetate as starting material. The transformation process from xerogel fibers to the ZnO fibers and the microstructure of the ZnO nanofibers have been investigated in detail. The diameter of the ZnO fibers was of 90-240nm and they were composed of polycrystalline nanoparticles of 20-45nm. A single ZnO nanofiber was obtained by using an improved collector and the electrical property of the nanofiber was studied.