A wire-rope- rapidly-replaceable pulley structure is disclosed, which belongs to fitness equipment. The pulley structure capable of rapidly replacing a wire rope comprises an open groove on a square tube, a left fixed plate and a right fixed plate embedded and fixed in the open groove of the square tube, a wire rope wound on a pulley, a pulley installed between the left fixed plate and the right fixed plate, a bolt shaft penetrating through shaft holes on the left fixed plate, the right fixed plate and the pulley, and a fixing nut of the bolt shaft. An arc guide plate is fixed in the square tube, wherein the arc guide plate is located at the upper side of the excircle of the pulley, and the arc shape of the arc guide plate and the excircle of the pulley are concentric. An arc groove convenient for the passing of the steel rope is further disposed on the cross section of the arc guide plate. The gap between the arc shape at the outer side of the arc guide plate and the excircle of the pulley is less than the diameter of the steel rope. The steel rope can be replaced without the need to detach the pulley; and the steel rope can smoothly penetrates through the arc groove on the pulley from one end and then penetrates out from the other end. The pulley structure capable of rapidly replacing a wire rope is very convenient in replacement, labour-saving and time-saving, and capable of being widely applied to various types of fitness equipment.