The invention discloses a metal covering wall brick and a preparation method and application thereof, and belongs to a building internal and external wall decoration material. The method comprises the following steps of: preparing a sheet metal into a metal cover or a metal cap according to the size of the wall brick, coating a layer of structural glue or foam glue in the metal cover, and then buckling the metal cover on an XPS or EPS insulated plate with wall brick or ceramic tile size to prepare the metal covering insulated wall brick; or coating a layer of adhesive mud or structural glue in the metal cover, and buckling the metal cover on an un-insulated material for internal and external walls of a house to prepare the metal covering un-insulated wall brick. The method has the advantages of simple production equipment, simple process and simple assembly; the metal insulated wall brick is light and safe in use; and the metal un-insulated wall brick is used for beautifying the city.