A liquid-cooled heat dissipation device is disclosed, comprising a main body, a centrifugal pump, an inlet pipe, an outlet pipe, a centrifugal fan and a motor. The main body comprises a shaft hole, liquid flow channels and airflow channels. The centrifugal pump guides a cooling liquid through the inlet pipe, main body and outlet pipe. The centrifugal fan guides air into the main body axially from the shaft hole. After passing through the centrifugal fan, the air forms centrifugal airflows and leaves the body radially through the airflow channels. With an extended flow path of the cooling liquid and the radial flow of the centrifugal airflow provided by the present invention, the temperature of the cooling liquid may be quickly reduced and the cooling effect may be improved. Thus, the structure is compact, small, light-weight, easy-to-assemble.