A connection device of an LED lamp and cooling fins is composed of a central tube unit, above which is connected with a ring-shape lamp seat, and below which is connected with a lower housing; and a plurality of cooling fins which are connected on surfaces of the lamp seat, the central tube unit, and a lower annular disk of the central tube unit. A sheet of each cooling fin is punched into at least one protruded member, and each protruded member of one cooling fin is abutted on a surface of the adjacent cooling fin; therefore, by the abutting of the protruded members of every two adjacent cooling fins, stability, intensity, and heat transmissibility of all the cooling fins can be improved, and spacing between every two adjacent cooling fins can be kept at a constant.