The invention discloses a method for preparing a graphene/sulfur/conductive polymer composite material used for the lithium-sulfur battery positive electrode. The method comprises the following steps: (1) mechanical mixing; (2) isostatic fusion; and (3) polymer cladding. According to the method, elemental sulfur is wrapped in a three-dimensional conductive network composed of graphene by using mechanical mixing, isostatic fusion, polymer cladding and other simple and practical means, so the excellent electrical contact between the elemental sulfur and the graphene can be kept, and the diffusion path of lithium ions is shortened, thereby ensuring that the electron conduction of an electrode material can not be lost. In addition, the elemental sulfur is cladded completely and uniformly by the conductive polymer, so that the direct contact between the polysulfide ion and the electrolyte in reactions is prevented effectively, and thus the initial charging/discharging efficiency and cyclic performance of the material are enhanced.