Composite heat dissipation system

The invention relates to the heat dissipation field and provides a composite heat dissipation system. The composite heat dissipation system includes a phase change structure and a vacuum chamber soaking plate which abut each other, wherein the phase change structure includes a rib, liquid metal alloy and an outer chamber, multiple ribs are disposed in the outer chamber at intervals, and the liquid metal alloy is loaded in a hollow structure formed by the outer chamber and the ribs. The composite heat dissipation system is advantaged in that heat transferred to the vacuum chamber soaking plate in one direction is transferred to other directions of the vacuum chamber soaking plate through the liquid metal alloy, the heat is absorbed and liquefied by utilizing the solid metal alloy in the outer chamber, heat dissipation efficiency of the vacuum chamber soaking plate is effectively enhanced, moreover, the waste heat of the vacuum chamber soaking plate is reduced, and heat dissipation of the vacuum chamber soaking