The invention belongs to a liquid cooler for cooling of an electronic component. The liquid cooler comprises a cooling plate with a multi-start spiral flow channel, a cover plate with fins and air flow holes, an air flow cooling cavity, a spiral groove cooling liquid heat dissipating plate, a cooling liquid storage cavity, a turbine, a fan and a motor. According to the invention, a cooling plate with a multi-start spiral flow channel structure is employed, wherein a cooling liquid flows symmetrically from inside to outside in the structure, thereby effectively overcoming the defects that the temperature of a traditional radiator increases continuously along the flow direction of a cooling liquid and a cooled electronic component generates unsymmetrical thermal stress and the like; and thecooling liquid that has worked or absorbed the heat is cooled by the air flow of the fan and subjected to heat dissipation processing of the fins, and then the cooling liquid is sent to the spiral flow channel cooling plate to carry out continuous internal circulation cooling on the electronic component. Therefore, the liquid cooler provided by the invention has the characteristics that the structure is compact, the cooling effect on the electronic component is good, the temperature adjustment range is wide, adverse effects of the thermal stress on the component are effectively reduced, the electronic component can be ensured to work efficiently, stably and safely in the working environment, and the service life of the electronic component can be prolonged.