The invention discloses a seamless steel tube for a boiler. The seamless steel tube comprises an outer tube, an inner tube, a supporting tube and a filling layer, wherein the outer tube and the inner tube are connected through the supporting tube; the supporting tube consists of three steel tubes; a regular tetrahedron framework structure is formed in a space; the vertex of the regular tetrahedron framework structure is connected with the outer tube, and the rest three points are connected with the inner tube; the filling layer is further arranged between the outer tube and the inner tube; and a thermal insulation material is filled in the filling layer. The seamless steel tube for the boiler disclosed by the invention is high in strength, good in thermal insulation property and long in service life.