Fabricated external wall thermal insulation system

The invention relates to the technical field of external wall heat preservation, in particular to an assembly type external wall heat preservation system which comprises a plurality of heat preservation plates installed on the surface of an external wall, and the opposite sides of every two adjacent heat preservation plates are provided with a containing groove and a sealing groove correspondingly. An extrusion part for extruding and pushing the surface of the outer wall, a sealing part embedded in the sealing groove in a sealing manner and a pushing part embedded in the accommodating groove in a sliding manner are arranged in the accommodating groove; the extrusion piece is slidably arranged on the side, facing the outer wall surface, of the insulation board in a penetrating mode in the thickness direction of the insulation board, the extrusion piece is provided with a pushing face inclining towards the sealing groove and used for pushing the pushing piece to the sealing groove, and the sealing piece is inst