A power LED lighting assembly includes power LEDs (each 1 watt, for example) mounted on a small circuit board of aluminum. To promote air ventilation, the LED circuit board is provided with air openings to communicate with the heat sink. A heat sink enclosure for accommodating the heat sink is also provided with air openings to communicate with the surrounding atmosphere. A micro fan is fixed above the heat sink for forced air ventilation. A temperature sensor is also installed to sense abnormal temperature increases in the assembly to adjust or reduce the volume of light and protect LEDs against abnormally high temperature. The micro fan is turned on for heat release automatically on a temperature increase.