The invention discloses a lithium-sulfur battery cathode material, a preparation method, and a lithium-sulfur battery, and belongs to the technical field of lithium-sulfur battery materials. The lithium-sulfur battery cathode material is a carbon-sulfur composite material, which is coated by a carbon cladding layer with a micro-porous structure. In the preparation method, under a vacuum condition, the raw materials are heated, just in one step, the sulfur and the carbon matrix are uniformly combined, the carbon precursor is carbonized, and the coating on the carbon-sulfur composite material is achieved. Compared with the conventional low-temperature coating method, the carbon cladding layer, which is carbonized at a high temperature and has a micro-porous structure, can form interactions just like the chemical bonds with the carbon-sulfur composite material; so that the micro-porous carbon cladding layer and the carbon-sulfur composite material are tightly combined together, thus the sulfur and discharge products cannot be easily dissolved in the electrolyte, the shuttling effect is prevented, the utilization rate of sulfur is improved, at the same time, the conductivity of the cathode material is better improved, and the cycle stability and capacity retention rate of the lithium-sulfur battery are both improved.