A retractable snap ring structure includes a snapping hook, a clamping seat, a receiving box, a bottom housing, a fixing plate, an upper washer, a lower washer, a vehicle body, a spring, and a small-sized spring. The hook portion of the snapping hook may be protruded outward from or retracted into the vehicle body by a simple pressing action, thereby facilitating the user using the retractable snap ring structure. Thus, when the snapping hook is not in use, the hook portion of the snapping hook may be retracted and hidden in the vehicle body, thereby preventing the hook portion of the snapping hook from protruding outward to hurt the people, and thereby increasing the lifetime of the snap ring structure.