The invention discloses a wall surface dry-hang structure for moldable GRG (fiberglass reinforced gypsum) decorative material, which comprises GRG decorative material (1), pre-buried stacking pieces (2) and a basic steel frame (4), wherein a number of pieces of GRG decorative material (1) are spliced to form a surface course of a wall surface; the pre-buried stacking pieces (2) are arranged in the GRG decorative material (1); and the pre-buried stacking pieces (2) are fixedly connected with the basic steel frame (4) through connecting bolts (3). The pre-buried stacking pieces (2) are T-shaped galvanized iron sheets. The pre-buried stacking pieces (2) are arranged according to the size and the weight distribution of the GRG decorative material (1). A reserved expansion joint is formed at an abutted seam formed between the GRG decorative material (1). The reserved expansion joint is filled with abutted seam agents (5). The wall surface dry-hang structure is simple and feasible to construct can solve the problem that an irregularly-shaped form is difficult to construct, can be formed optionally according to the design of designers, and can be produced and divided in mass. The field processability is good, the installation is rapid and flexible, and large-area seamless close assembly can be achieved so as to form integral modeling.