Cooling and energy-saving system for building outer wall

The utility model relates to the technical field of building facilities, and discloses a building outer wall cooling and energy-saving system which comprises a wall body and a light barrier. The wall body is provided with a sliding channel allowing the light barrier to slide along a preset path and a light inlet channel allowing light to enter. The light barrier comprises a first plate body with first reflectivity and a second plate body with second reflectivity and corrosion resistance; the first reflectivity is greater than the second reflectivity; the first plate body and the second plate body are sequentially arranged along a preset path; the sliding channel and the light inlet channel intersect to form an intersection space. The intersection space is located on the moving path of the first plate body and the moving path of the second plate body. The wall body is installed on the outer wall of a building, the plate bodies for shielding are automatically adjusted according to the external air temperature a