A self-drainage anchor cable system is provided, wherein a drainage section (15) is arranged above the internal anchoring section (14) of an anchor cable; a first end of the steel strand (2) extends into a bottom of the borehole (1); the isolation pipe (3) is sleeved on the steel strand (2) in the drainage section (15), and the permeable pipe (4) is sleeved on the isolation pipe (3); a length of the isolation pipe (3) is larger than a length of the permeable pipe (4), and there is a space (5) between the isolation pipe (3) and the permeable pipe (4); the water stop rings made of water-expanding rubber (6) are provided at both ends of the isolation pipe (3), and end portions of the permeable pipe (4) are in contact with the water-expending rubber water stop rings (6) A construction method for the self-drainage anchor cable system is also provided.