A treadle assembly of an exercise equipment including a mounting seat, a treadle, a bearing bracket. The mounting seat includes a supporting groove in the middle thereof and two indentations in the middle of both sides thereof. The treadle includes a rigid cylinder at the bottom thereof. The inside of the rigid cylinder is filled with soft filling material. A screw bolt is fitted in the middle of the soft filling material for securing the mounting seat to the treadle by fixing the screw bolt in the indentations of the mounting seat in collaboration with screwing elements. The bearing bracket is attached to a bottom side of the supporting groove of the mounting seat. Meanwhile, a bearing is disposed at each of four corners for a full contact with the periphery of the rigid cylinder. Thus, a plurality of connecting holes is formed at both sides of the mounting seat for securing the mounting seat to a treadle plank of an exercise equipment.