Discloses herein is a shielding and heat dissipation device comprising a conductive bracket (1) provided on a PCB around a shielded heat-generating electronic component, and electrically connected to a conductive layer of the PCB; a heat sink (2), which is arranged above the heat-generating electronic component (3) and is provided with a conductive surface electrically connected to the conductive bracket (1). With the conductive surface, which may be used to replace a top cover of a prior art shielding case, developed on the bottom or sidefaces of the heat sink, an effective shielding cavity is formed by conductively connecting the conductive surface of the heat sink to the other parts of the shielding case. That is to say, the conductive surface of the heat sink serves as a part of the shielding case, so that the heat sink may play a role in electromagnetic shielding as well as in dissipating heat sufficiently.