Lithium-sulfur batteries(LSBs) are considered as one of the most promising energy storage systems due to the ultra-high theoretical energy density(2600 Wh/kg) and ultra-high theoretical specific capacity(1675 mAh/g), environmental friendliness and low-cost of sulfur cathode. However, the insulation of sulfur cathode, the volumetric strain and the “shuttle effect” of polysulfides lead to problems such as low utilization rate of active materials, poor cycle stability and low redox kinetics, which seriously hinder the commercial development of LSBs. Recent studies have shown that transition metal sulfides as host or additives can significantly improve the electrochemical performance of LSBs cathode materials. In this paper, the modification mechanism of transition metal sulfides in LSBs cathode materials is reviewed from four aspects: equivalent/common positive electrode effect, conductivity enhancement, LiPSs adsorption and electrochemical reaction catalysis. It is pointed out that multi-transition metal sulfides composite, nano-crystallization and quantization as important areas for increasing the specific surface area and active sites should be used as transition metal sulfides for lithium-sulfur battery cathode materials, which can greatly improving the electrochemical performance of LSBs.