A heat dissipation device includes a heat sink and a back plate assembly thermally independent from the sink. The back plate assembly includes a body facing a bottom surface of the heat sink and a heat-dissipating member thermal connecting to the body. The heat sink is used for absorbing heat generated by a heat-generating electronic component from a top side thereof. The back plate assembly is used for absorbing the heat generated by the heat-generating electronic component from a bottom side thereof. The heat sink and the back plate assembly are connected together by fixing members extending from the heat sink through a printed circuit board on which the electronic component is mounted to threadedly engage with the back plate assembly.