A liquid cooling system includes a cooling body (10), and a liquid circulation module (20). The cooling body comprises a cooling base (11) for thermally contacting a heat source, and a heat sink (14) mounted on the cooling base. An internal flow path is defined in the cooling body, for heat exchange with coolant. At least two passages (15) are formed through the heat sink. The liquid circulation module defines a plurality of external flow paths coupled to the internal flow path of the cooling base, thereby forming a loop for circulation of the coolant. The external flow paths comprises at least two output paths extending through the at least two passages of the heat sink, and along which the coolant that exits the internal flow path passes through the heat sink for cooling.