Skin structure of composite big plate type square cabin and method for reducing thermal deformation of skin

The invention discloses a skin structure of a composite big plate type square cabin. The skin structure comprises an outer aluminum skin, a steel skin, basswood, square steel and an inner skin, wherein the outer aluminum skin, the steel skin, the basswood, the square steel and the inner skin are bonded with one another in sequence; multiple groups of basswood and square steel are correspondingly arranged; foams are arranged between each group of basswood and square steel and the adjacent group of basswood and square steel; and the foams are respectively bonded with the inner skin and the steel skin. The invention also discloses a method for reducing the thermal deformation of the skin. After the structure is adopted, the environment temperature is increased so that the temperature of the outer aluminum skin on the external side is increased and then the thermal deformation of a composite plate is less than that of the single outer aluminum skin; the reliability in bonding the internal side of the outer aluminum skin and a basswood strip in a framework structure is improved; and problems of unsticking and bumping at high temperature due to pure adoption of the single aluminum skin are effectively solved.