The invention relates to a surface thermal insulation structure of a high temperature device. The surface thermal insulation structure is particularly applicable to surface thermal insulation of a steam turbine. The surface thermal insulation structure comprises insulation pins welded on the surface of the high temperature device and an internal thermal insulation layer formed by at least one group of composite thermal insulation structures; the internal thermal insulation layer comprises a spraying ceramic fiber layer, a nano hole aerogel thermal insulation layer and a steel wire mesh layer from inside to outside; the spraying ceramic fiber layer is formed by spraying ceramic fiber mixed with a high temperature resistant binding agent, and can be firmly absorbed to the surface of the high temperature device, and the influence from the surface unevenness of the high temperature device and a phenomenon that the root of a connecting pipe can not be applied with cut thermal insulation cotton in place easily are eliminated. The surface thermal insulation structure is simple in structure and reasonable in design, and has the advantages that the thermal insulation integrity is good, the connection is firm, the required insulation thickness is low, the construction is easy, the surface thermal insulation structure is free from the influence from the surface unevenness, and the construction of a special-shape part is facilitated.