The invention discloses a preparation method of porous carbon-loaded nanometer metal sulfide and belongs to the technical field of nano-materials. The method utilizes a solvothermal method for a reaction method and comprises that a carbohydrate source as a carrier precursor and a soluble metal salt as a carrier precursor are heated and stirred to form a uniform phase, the uniform phase is processed to form porous carbon-loaded nanometer sulfide precursor nano-particles by a high pressure solvothermal method, and the porous carbon-loaded nanometer sulfide precursor nano-particles are reduced or calcined at a high temperature to form porous carbon-loaded nanometer sulfide particles. The preparation method solves sintering problems of nano-particles in a heat treatment process and produces a needed crystal phase under this premise of nano-particle monodispersion. Through control of synthesis conditions, parameters such as product size and composition can be adjusted. The preparation method has the advantages of wide application scope, simple operation and low cost and is suitable for preparation of metal sulfide nano-particles.