A graphene heating thermal preservation sleeve for a wellhead of an oil-gas well, comprising a high-temperature-resistant thermal preservation layer, a heating layer, electrode layers, a waterproof anti-static thermal preservation layer and a housing, wherein the heating layer is a graphene layer; wherein the high-temperature-resistant thermal preservation layer, the graphene layer, the electrode layers, a high-temperature-resistant ceramic layer, the waterproof anti-static thermal preservation layer and the housing are attached together in sequence; wherein the graphene heating thermal preservation sleeve for a wellhead of an oil-gas well is composed of two parts, and after the two parts of the heating thermal preservation sleeve for a wellhead of an oil-gas well are buckled together, an oil-gas well wellhead apparatus can be wrapped in the graphene heating thermal preservation sleeve for a wellhead of an oil-gas well; and wherein corresponding sealing grooves are formed in the housing junction surface of the two parts of the graphene heating thermal preservation sleeve for a wellhead of an oil-gas well, characterized in that the two parts of the graphene heating thermal preservation sleeve for a wellhead of an oil-gas well are buckled through two or more than two hasps; wherein one of the two parts of the graphene heating thermal preservation sleeve for a wellhead of an oil-gas well being installed from one side of a valve handle is provided with five valve handle through holes for five valve handles to penetrate through the corresponding valve handle through holes to be buckled with the other part, and wherein sliding blocks and sliding block hasps corresponding to the positions of the five valve handles are installed. wherein the high-temperature-resistant thermal preservation layer, the graphene layer, the electrode layers, a high-temperature-resistant ceramic layer, the waterproof anti-static thermal preservation layer and the housing are attached together in sequence; wherein the graphene heating thermal preservation sleeve for a wellhead of an oil-gas well is composed of two parts, and after the two parts of the heating thermal preservation sleeve for a wellhead of an oil-gas well are buckled together, an oil-gas well wellhead apparatus can be wrapped in the graphene heating thermal preservation sleeve for a wellhead of an oil-gas well; and wherein corresponding sealing grooves are formed in the housing junction surface of the two parts of the graphene heating thermal preservation sleeve for a wellhead of an oil-gas well, characterized in that the two parts of the graphene heating thermal preservation sleeve for a wellhead of an oil-gas well are buckled through two or more than two hasps; wherein one of the two parts of the graphene heating thermal preservation sleeve for a wellhead of an oil-gas well being installed from one side of a valve handle is provided with five valve handle through holes for five valve handles to penetrate through the corresponding valve handle through holes to be buckled with the other part, and wherein sliding blocks and sliding block hasps corresponding to the positions of the five valve handles are installed.