A structure of water-saving device includes a base, an adjusting ring and a gland. The adjusting ring is mounted in a water-inlet channel. The gland is movably positioned in the base to limit the adjusting ring. A central part of a top surface of the gland sinks downward to form a recess. When water flow impacts the gland, the gland pushes the adjusting ring, such that the adjusting ring is deformed. Since a difference of pressure occurs between a top and bottom surfaces of the gland, the larger the water pressure is, the larger the force from the gland toward the adjusting ring becomes; thus the degree of deformation of the adjusting ring also becomes large, such that the area between the adjusting ring and the bottom surface of the base for water flowing through decreases and the flow of water gradually achieves a stable value.