A heat-dissipating device includes a MOSFET heat dissipator, a south bridge heat dissipator, a north bridge heat dissipator and a water block connector. A heat pipe is provided between each heat dissipator to connect these heat dissipators in series. Further, the north bridge heat dissipator has a heat-dissipating bottom plate and a heat-dissipating body attached to a half portion of the heat-dissipating bottom plate. Further, the water block connector comprises a hollow base and two connecting tubes that are provided on two locations of the base and in communication with each other. The base of the water block connector is attached to the other half portion of the heat-dissipating bottom plate of the north bridge heat dissipater. When the water cooling is used, the two connecting tubes of the water block connector can be connected in series with a water-cooling circulation system.