The heat dissipation structure of the backlight module of the present invention comprises a circuit board, a heat-conductive element (such as thermally conductive glue) and a light-emitting diode (LED) chip, wherein the circuit board has an electric circuit layer and a heat conductive layer respectively formed on two opposite surfaces thereof. The circuit board has a plurality of through holes penetrating through the electric circuit layer and the heat-conductive layer of the circuit board, wherein each of the through holes is filled with heat-conductive material. The heat-conductive element is placed on the circuit layer and covers the through holes, and the LED chip is disposed on the heat-conductive element and is electrically connected to the electric circuit layer.