The hydrothermal method was used to prepare MoS2 photocatalyst with the raw materials of MoO3 and KSCN,and the prepared products were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM).The catalytic performance of MoS2 photocatalyst obtained at different reaction temperatures was studied,meanwhile the effects of different concentrations and different pH on degradation rate of methylene blue (MB) were investigated.The results show that those prepared photocatalyst samples are of nanometer scale,which exhibits better photocatalytic activity.When preparing MoS2 photocatalyst,the higher temperature of the hydrothermal reaction,the greater the photocatalytic performance will be,and the crystallinity can be higher as well.As for degrading MB,the higher the concentration of MB is,the worse the degradation effect will be.The prepared photocatalyst was observed to show better degrading performance for MB solution under acidic condition,when pH was taken into consideration.