The invention relates to the technical field of seismic reduction and seismic isolation of engineering structures, and provides a horizontal limiting mechanism for a seismic isolation layer. The first end of a first steel wire rope penetrates through the side wall, opposite to a second annular base, of a first annular base arranged outside a first rubber support and is connected with the first rubber support, and the second end of the first steel wire rope winds around the outer wall of the second annular base, penetrates through the side wall, back on to the first annular base, of the second annular base and is connected with a second rubber support; the first end of a second steel wire rope penetrates through the side wall, opposite to the first annular base, of the second annular base and is connected with the second rubber support, and the second end of the second steel wire rope winds around the outer wall of the first annular base, penetrates through the side wall, back on to the second annular base, of the first annular base and is connected with the first rubber support. When an earthquake occurs, by means of restrictions of the first steel wire rope and the second steel wire rope, a horizontal limiting effect on the first rubber support and the second rubber support is achieved.