An LED lamp with replaceable light unit comprising: a heat dissipation housing having an opening at one end and a joint portion at another end, and the opening inside having a spacer with a hole and a screw thread portion; the heat dissipation housing having a chamber to communicate with the hole and the joint portion; a metal connector disposed to the joint portion, the metal connector having a screw connection portion and a lamp head connected thereto in insulation; a driver circuit board disposed inside the chamber, the driver circuit board having two power input wires (31, 31') and two power output wires (32, 32'), one of the power input wire electrically connected to the screw connection portion, and the other power input wire electrically connected to the lamp head; a light unit slice having a substrate, the light unit slice having a circuit board disposed on a surface thereof and insulated thereto, electrically connecting to at least one light emitting element and further including two welding areas for electrically connecting to two power source wires; and a shade disposed on the opening, the shade having a connecting portion thereon; and a pad is disposed between the shade and the light unit slice, characterised in that the opening inside having the screw thread portion on the inner surface; and the connecting portion of the shade having a screw thread face on its outer surface for screwing to the screw thread portion of the opening; the two power output wires (32,32') being connected to an joint; and the two power source wires being connected to a joint to connect the power output wires (32,32') with the two power source wires. a heat dissipation housing having an opening at one end and a joint portion at another end, and the opening inside having a spacer with a hole and a screw thread portion; the heat dissipation housing having a chamber to communicate with the hole and the joint portion; a metal connector disposed to the joint portion, the metal connector having a screw connection portion and a lamp head connected thereto in insulation; a driver circuit board disposed inside the chamber, the driver circuit board having two power input wires (31, 31') and two power output wires (32, 32'), one of the power input wire electrically connected to the screw connection portion, and the other power input wire electrically connected to the lamp head; a light unit slice having a substrate, the light unit slice having a circuit board disposed on a surface thereof and insulated thereto, electrically connecting to at least one light emitting element and further including two welding areas for electrically connecting to two power source wires; and a shade disposed on the opening, the shade having a connecting portion thereon; and a pad is disposed between the shade and the light unit slice, characterised in that the opening inside having the screw thread portion on the inner surface; and the connecting portion of the shade having a screw thread face on its outer surface for screwing to the screw thread portion of the opening; the two power output wires (32,32') being connected to an joint; and the two power source wires being connected to a joint to connect the power output wires (32,32') with the two power source wires.