A cooling device for cooling electronic components includes a base plate, a power source, and a cooling module. The cooling module includes a cooling sheet and a thermal conductive base. The cooling sheet includes a hot surface and a cooling surface. The thermal conductive base is located above the cooling surface of the cooling sheet, and configured to support electronic components on a printed circuit board and transfer heat between the electronic components and the cooling surface. When the cooling sheet is powered on, the cooling surface is in a constant state of low temperature. Due to the heat transfer between the cooling surface and the thermal conductive base, heat from the electronic components can be transferred from the thermal conductive base to the cooling surface continuously.