An LED optical assembly for automotive low-beam headlamps, including: a lens, a lens frame, a light source frame assembly, and an LED light source. The lens includes a main lens and a plurality of reflectors. The main lens is located in the front of the LED optical assembly and the reflectors are scattered therearound. At one side of the main lens, four sets of the reflectors, which are symmetrical in shape, are respectively disposed at the left part and the right part thereof, and in a back of the main lens, six sets of the reflectors, which are symmetrical in shape, are respectively disposed at the left part and the right part thereof.