The MoS2 nanostructures with different morphologies were synthesized by a facile hydrothermal method using precursors of ammonium molybdate ((NH4)6Mo7O24.4H2O), thiourea (CH4N2S) and hydroxylammonium chloride (NH2OH.HCl). As-prepared MoS2 samples with different growth temperatures of 160, 180, and 200 °C were characterized by Raman spectroscopy, field emission scanning electron microscopy (FESEM) and x-ray powder diffraction (XRD). Raman data of all samples showed the two active modes at about 380 cm-1 and 406 cm-1, which were corresponding to in-plane vibration of Mo and S atoms as well as to out-of-plane vibration of S atoms of MoS2 nanostructures. XRD results also revealed characteristic diffraction peaks of the MoS2 for all samples grown at different temperatures. However, the XRD pattern of the MoS2 grown at 200 °C exhibited a more pronounced peak at approximately 12.1°, corresponding to the diffracted peak of (002) lattice plane of MoS2. It implied that the MoS2 nanostructures synthesized at 200 °C showed a better crystallinity compared to the rest. The findings indicated that reaction temperature has significant effects on the morphology and crystal structure of the as-prepared products. It was found that the optimal growth temperature was 200 °C. Under this condition, the nanostructures are about more than 100 nm in length and 10 nm in thickness.