The invention relates to a composite exterior wall decorative panel. The composite exterior wall decorative panel comprises a decorative panel body. The decorative panel body comprises a base plate and a surface plate or a surface layer arranged on a surface of the base plate, and a heat exchange medium layer is arranged between the base plate and the surface plate or between the base plate and the surface layer. The composite exterior wall decorative panel has the advantages of economic applicability, flame resistance, light weight, small shrinkage, environmental protection, heat preservation, moisture prevention and good durability. The problems of strong penetration, rapid penetration and deep penetration of an uv-curable penetrating agent and a fiber reinforced calcium silicate board or a fiber cement board can be solved, a film is formed through deep curing, and a three-dimensional chemical network crosslinking reaction can be formed with UV putty and UV sealing paint so that theadhesion problem of a decorative surface layer and the base plate can also be solved. The invention also provides a flame retardant material. Adhesion properties of the anti-flaming decorative panel prepared by the method meet the requirements of the national standard and the base material is given the flame-retardant property; moreover, mechanical properties of the base material can not be influenced, and the formaldehyde emission is also above the level E1, so that the panel is safe and environmentally friendly. At the same time, the natural texture of wood is kept, and the decorative effectis good.