The invention relates to X-shaped structure sports underwear, the upper edges of the front of the sports underwear are connected with shoulder straps in a sewing manner, the shoulder straps are connected with a first back middle piece to form an X-shaped structure, the edges connecting the front, the shoulder straps and the back middle piece of the underwear in the sewing manner form a neck line of the underwear; two sides of a first back side piece are respectively connected with the first back middle piece and the front of the underwear in the sewing manner, the edges connecting the front, the first back side piece, the first back middle piece and the shoulder straps of the underwear in the sewing manner form armholes of the underwear; the bottom edges of the front, the first back side piece and the first back middle piece are connected with elastic bottom edges in the sewing manner, the sewed first back middle piece and the two sides of the elastic bottom edges are respectively provided with a hook and a hook loop in the sewing manner, an inner layer structure adopts inelastic fabric so as to improve the stability of breasts in the state of motion, X protecting structural design can guarantee stable support in four directions, namely vertical and horizontal directions, and the physical displacement of the breasts in the state of the motion is reduced.