A series-connected heat dissipater coupled by heat-pipe used for the interface cards of a computer system. Wherein, a plurality of additional auxiliary dissipaters are provided onto the insertion slots adjacent to the interface cards, and are connected to the main dissipater through heat pipe, hereby effectively solving the heat dissipation problem of the interface cards, so that the main-machine-board will not be bent and deformed due to the overweight caused by the interface cards.