A combinational LED lamp includes an insulating housing, a first conductive contact, a second conductive contact, and an LED body. The insulating housing includes a first engaging surface with a first engaging portion and a second engaging surface with a second engaging portion. The first engaging portion is engaged with the second engaging portion. The two conductive contacts are all fixed on the insulating housing. Both the two conductive contacts include an integral internal section and two exposure sections exposing at the first engaging surface and the second engaging surface of the insulating housing. Two terminals of the LED body are each electrically connected with the internal section of the first conductive contact and of the second conductive contact. Therefore, multiple LED-lamp units can be incorporated so as to form various configurations of LED-lamp combinations.