This paper describes a procedure of synthesizing MoS2 nanofibers with hexagonal structure. Polyvinyl alcohol (PVA)/Ammonium tetrathiomolybdate (ATTM) composite nanofibers were prepared by a sol–gel method and an electrospinning technique. Subsequently, the MoS2 nanofibers were derived from reduction of these precursor composite fibers at 450 °C under a H2 atmosphere for 2 h, and calcinating at higher temperature under an Ar atmosphere for 6 h. The precursor composite nanofibers and the MoS2 nanofibers were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the crystalline phase and fiber morphology were largely influenced by the calcination temperature in Ar atmosphere, the diameter of MoS2 nanofibers distributes from 50 nm to 200 nm.