The utility model relates to a technology for preventing cooling water leakage on a steel wire high-speed hot-dip galvanizing line, and discloses a water stop device for preventing cooling water leakage during steel wire hot-dip galvanizing. The device is characterized in that the connecting section of a first water stop plate and a second water stop plate adopts an inverted V-shaped structure; the first water stop plate and the second water stop plate are mounted between the lower part of an air seal device and the upper part of an electromagnetic wiping device; circular holes are formed at the top of the inverted V-shaped structure; galvanized steel wires penetrate the circular holes; and the electromagnetic wiping device is covered by the first and the second water stop plates when a user observes from the overlooking section. The device avoids production semi-circular indentations which are caused by water dripped into an electromagnetic chamber of the electromagnetic wiping device and further result in zinc scars on the galvanized surfaces of steel wires.