An LED track light device includes a plurality of LED-units that fit within a track means. At least one LED element(s) is fitted within the LED-unit's geometric construction, and leads of the LED are connected by conductive means, resilient conductive means, contact means, and/or bus means to deliver electric signal from an AC or DC power source, circuit means, switch means, sensor means, timer means, and/or control means to the element(s) to provide a desired area-illumination light function. The LED-units have a geometric construction and space to allow the element(s) to be fixed in position or incorporated with reflector means that may be arranged to rotate, swivel, or tilt. Hanging means or other electric devices also can added to the said LED track light device or the LED-units to add more practical extra functions.