The invention belongs to the field of building materials, and relates to a soft-packaging light external decorative board and a preparation method thereof.The soft-packaging light external decorative board is obtained by taking vinyl resin, acrylic modified epoxy resin, organic silicon resin and a light inorganic material as main materials through rendering, vibrating, vacuumizing and curing molding.Compared with a traditional exterior wall decoration material, the soft-packaging light external decorative board has the advantages of being small in weight, high in hardness, dazzling and adjustable in pattern, excellent in weather resistance, high in bonding strength with cement and excellent in impact resistance and has the very good application and popularization value.