The invention provides a single-double angle steel transition node which is used for connection between a single rod of angle steel and double-spliced angle steel which are disposed in the same direction in an electric transmission line angle steel tower. The node is improved in that the node comprises connecting plates and filling plates, wherein the connecting plates are disposed between two limbs of the single rod of angle steel and the double-spliced angle steel which are mutually perpendicular and adjacent respectively; and the filling plates are disposed between the two limbs of the single rod of angle steel and the double-spliced angle iron which are mutually parallel and adjacent respectively. In comparison with the prior art, the single-double angle steel transmission node provided by the invention has the advantages that construction and layout are smooth and compact; the appearance is concise; a wind prevention area of the overall structure is reduced; external loads are reduced; force bearing performance of the overall structure is improved; construction technologies are simple; and production efficiency is greatly increased.