Abstract: Unsupported MoS2 were obtained from the decomposition of ammonium tetrathiomolybdate (ATM) at variable temperatures (200-600 ℃) under N2. The effect of calcination temperature on the HDS activity of MoS2 using ammonium tetrathiomolybdate (ATM) as precursor was tested. The structures and properties of the catalysts were investigated by means of BET, XRD, SEM, TEM and XPS. The dibenzothiophene HDS activity was studied in an autoclave reactor. The results indicate that as the calcination temperature rises, the surface area and crysatllinity gradually increase. The characterizations show that the properties of the catalysts are affected by the amount and valence state of S. The optimal calcination temperature for the ATM was 400 ℃, resulting in the highest catalytic activity.