Cooling head device of water-cooling mold and water-cooling mold assembly

The utility model provides a cooling head device of a water-cooling die, which comprises a die connector, an extension pipe and a liquid inlet and outlet casing, a liquid inlet and a liquid outlet are arranged on the liquid inlet and outlet casing, and a threaded connection structure is arranged at one hollow cylindrical end of the die connector and used for being connected with a water-cooling hole on a die casing. The other end of the mold connector is connected with an extension pipe, the extension pipe comprises an outer pipe and an inner pipe which are mutually nested inside and outside, the outer pipe and the inner pipe are coaxially arranged at an interval, the inner pipe axially penetrates through the mold connector and extends into a water cooling hole in the mold, the inner pipe is communicated with a liquid inlet, and a gap between the outer pipe and the inner pipe is communicated with a liquid outlet; the liquid inlet and outlet shell is hermetically connected and matched with the extension pipe,