The utility model discloses a thermal insulation wall surface layer venting device, and belongs to the technical field of external thermal insulation on walls. The thermal insulation wall surface layer venting device comprises polystyrene boards arranged on a base wall, horizontal joints and vertical joints are respectively reserved between two adjacent polystyrene boards, intersections of the horizontal joints and the vertical joints are communicated with each other, wedge strip polystyrene boards serving as fillers are arranged on the outer sides of the horizontal joints and the vertical joints, the horizontal joints and the vertical joints are filled with the wedge strip polystyrene boards, air ducts are formed in the horizontal joints and the vertical joints, exhaust holes are formed in the air ducts from space to space and connected with bent exhaust pipes matched with the exhaust holes, and junctions of the exhaust holes and the bent exhaust pipes are sealed by polyurethane foam. The thermal insulation wall surface layer venting device is fine in air permeability, water vapor in the base wall and a thermal insulation layer can be timely exhausted to atmosphere, condensation of the water vapor between a thermal insulation board and the wall is avoided, a coating decoration layer is effectively prevented from blistering and falling off, and construction period cannot be affected when the humidity of a base layer and the thermal insulation layer exceeds standards.