A dimming processing system for an LED lamp includes a signal input area, a plurality of color trigger switches located in the signal input area, an HSV color selection area composed of the plurality of color trigger switches, and a non-color selection area located in the signal input area, a value module, and a dimming processing module. The value unit is configured to turn on one of the selected color trigger switches in the last selected HSV color selection area having the largest distance from the pole of the polar coordinate system when one of the color trigger switches is sequentially switched to select one of the selection switches or when one selection switch and one color trigger switch are simultaneously selected, and the HSV value corresponding to the color trigger switch is extracted, thereby avoiding blurring and uncertainty of finger sliding.