The invention discloses an artware fixing mechanism applicable to multiple sizes. The artware fixing mechanism comprises a fixing base. A containing groove is formed in the upper surface of the fixingbase. Multiple arc-shaped fixing clamping pieces are uniformly arranged around the containing groove. All the fixing clamping pieces are located on the same circumference. The bottom ends of the circumference fixing clamping pieces are connected to the surface of the fixing base in a sliding manner. A fixing top rod is arranged between every two adjacent fixing clamping pieces. The fixing top rods are connected with the fixing base through support rods in a sliding manner, wherein the support rods are vertically arranged. The fixing top rods are parallel with the motion directions of the fixing top rods. A suction disc is connected to the end, close to the containing groove, of each fixing top rod. According to the fixing mechanism, by means of the fixing clamping pieces and the fixing top rods, bulging portions and sunken portions of an object can be fastened at the same time; the surface of the object can be stressed uniformly; the force bearing area is increased; stability of the object is improved; and meanwhile, safety, achieved in the clamping process, of the object is guaranteed.