The utility model discloses an extension jib rod of a down-the-hole drill comprising a slide rack (1) on the down-the-hole drill. The extension jib rod of the down-the-hole drill is characterized in that a hydraulic thread of the slide rack (1) is L; and L is longer than 10,000 mm. The extension jib rod of the down-the-hole drill is simply structured with smart design and reduced procedures, so work efficiency can be improved.