A ring accessory comprises an outer loop and an elastic piece placed in the outer loop. The outer loop comprises a lateral loop and a top cover located above the lateral loop. The top cover has a hole for a ring head passing through. An inner side of the top cover at an edge of the hole comprises at least three deep recesses, and a shallow recess between every two adjacent deep recesses. A distance from the deep recess to hole center is greater than a distance from the shallow recess to the hole center. The elastic piece has recesses corresponding to the deep recesses and shallow recesses on the top cover. The elastic piece is an annulus with a wave shape, the elastic piece deep recesses are located at the bottom of the wave, and the elastic piece shallow recesses are located at the top of the wave.