A heat-wing includes: a sealed hollow chamber including two plates and a frame connecting the two plates; a capillary structure layer closely attached to an inner surface of the chamber; and a phase transition working medium sealed in the chamber. A portion of the frame or a portion of a periphery of one of the two plates serves as an evaporation area of the heat-wing, and the rest portion of the chamber serves as a condensation area of the heat-wing. The heat-wing has an increased vapor passage area, liquid working medium flow-back passage width and condenser heat transfer area and a reduced evaporator center-to-edge distance, and is hence capable of achieving a great improvement in heat transfer limit and heat flux density.