A liquid-cooling heat sink includes a base (10), a heat exchanger (30), a housing (20), an inlet (26) and an outlet (27). The heat exchanger (30) has a hollow (33) formed therein, and is thermally coupled to the base (10). The housing (20) has a chamber (24) formed therein, and is placed over the base (10). The chamber (24) is separated by the heat exchanger (30) into a first sub-chamber (241) and a second sub-chamber (242). The first sub-chamber (241) is in fluid communication with the second sub-chamber (242) through a plurality of microchannels (32) radially formed within the heat exchanger (30). The inlet (26) is fluidly connected to the first sub-chamber (241) so as to impinge liquid coolant to a top surface of the base (10).