A liquid cooling system includes a cooling unit (100) and a coolant driving unit (200). The cooling unit includes a first cooling body (110) defining a first cavity, a second cooling body (130) defining a second cavity in communication with the first cooling body (110), and a heat sink (150) sandwiched between the first and second cooling bodies. The coolant driving unit is in flow communication with the first and second cooling bodies respectively, so that the first and second cooling bodies and the coolant driving unit together form a loop. Circulation of the coolant in the loop causes the heat generated by the heat generating component to be capable of being transferred from the first and second cooling bodies to the heat sink for dissipation.