A light emitting diode (LED) package structure including a first substrate, an LED chip, a second substrate, and a thermoelectric cooling device is provided. The first substrate has a first surface and a corresponding second surface. The LED chip suitable for emitting a light is arranged on the first surface of the first substrate, and is electrically connected to the first substrate. The second substrate is below the first substrate, and has a third surface and a corresponding fourth surface. The third surface faces the second surface. The thermoelectric cooling device is arranged between the second surface of the first substrate and the third surface of the second substrate for conducting heat generated by the LED chip during operation.