The utility model relates to a reactor with a plasma high-temperature carbon conversion structure. The reactor comprises an upper connection flange, an outer cylinder, an air inlet, a shunt cylinder, a porous cylinder, a lower connection flange and a temperature measuring device which are connected sequentially, wherein the upper connection flange, the outer cylinder, the porous cylinder and the lower connection flange form a cavity, and other components are connected to the cavity sequentially. Steam is introduced to the surface of a hot wall, and passes through granule gaps to form an air boundary layer with excellent thermal insulation and dynamic stable property so as to achieve the effects of excellent cooling and protection.