Abstract: The present invention provides a compound wick structure of a vapor chamber, which comprises a first plate and a second plate. The first plate has a first side and a second side. The second plate has a third side and a fourth side. The first plate and the second plate are assembled together to form a sealed chamber. The third side of the second plate is provided with a mesh or a fiber body; the third side has at least one heated zone having a first sintered-powder structure. The first sintered-powder structure is selected to be connected to or in contact with the mesh or the fiber body. A working liquid is disposed in the sealed chamber. By means of the arrangement of the compound wick structure, the vertical and horizontal flow-back efficiencies of the working liquid are enhanced and the efficiency of liquid-vapor cycle is increased.