An anti-lock brake structure includes a brake base having a curved guiding portion formed thereon and a slidable holder. The slidable holder has a curved guiding groove defined therein for receiving the brake base. Two anti-lock inclined surfaces are positioned between the curved guiding portion and the curved guiding groove. Each anti-lock surface has a shallow section and a deeper section. Two wheel sets are disposed between the curved guiding portion and the curved guiding groove. A seat member connected to the slidable holder and receives an elastomer. A brake shoe is connected to the slidable holder. Each wheel set rolls and reciprocates between the shallow section and the deeper section of the corresponding anti-lock inclined surface, such that the brake shoe is tightly or loosely rubbed against a wheel rim of the vehicle to provide an anti-lock brake effect.