The present invention is directed to a light-emitting diode (LED) illumination apparatus. The apparatus includes a housing, an LED substrate, at least two electrical-insulation clamping members and associated screws, and a heat-conduction pad. At least one LED chip is fixed on the surface of the LED substrate. Each electrical-insulation clamping member has a threaded hole for screwing the screw in order to fasten the electrical-insulation clamping member to the housing; and each electrical-insulation clamping member has a recess for clamping the LED substrate. The heat-conduction pad is disposed between the housing and the LED substrate, and is used to conduct heat generated by the LED chip.