A manufacturing method of heat dissipation unit includes steps of: providing a mold having an upper mold section and a lower mold section, the lower mold section being formed with a receiving depression and at least one sink; providing an upper plate, a lower plate, a capillary structure and at least one heat conduction member, the heat conduction member being positioned in the sink, the lower plate, the capillary structure and the upper plate being sequentially positioned in the receiving depression, then the heat conduction member, the lower plate, the capillary structure and the upper plate being thermally pressed and connected with each other by means of the upper and lower mold sections; and integrally connecting the heat conduction member with the lower plate when the upper and lower plates are thermally pressed and connected to form the plate body by means of the upper and lower mold sections.