The mountain drill double-tube follow-up drilling tool mainly consists of an inner drill pipe, a down-the-hole hammer and an outer casing. Wherein, the down-the-hole hammer is coupled with the inner drill rod, and the inner drill rod and the down-the-hole hammer are rotated by the mountain drill power head, and the compressed air is sent to the down-hole hammer through the center of the inner drill rod to drive the down-the-hole hammer to vibrate. The upper part of the lower end of the down-the-hole hammer is formed into a step shape and a keyway. The outer casing is divided into upper and lower parts. The lower part is made into an empty sleeve connection. When the power head drives the drill bit to rotate through the inner drill rod, the outer sleeve does not rotate with the drill bit due to the coupling of the empty sleeve, but only the vertical movement of the inner drill rod to the formation. Therefore, the resistance torque of the power head is reduced; the inner wall of the bottom end of the outer sleeve is designed in a stepped shape, and the key groove is matched with the step portion of the lower end of the down-the-hole hammer. When the down-the-hole hammer is drilled in the forward direction, the lower end of the outer sleeve is rotated and followed up; the cuttings cut during drilling are ejected from the gap between the inner drill rod and the outer sleeve. After drilling to the predetermined deep plating, while the power head is reversed, the down-the-hole hammer is disengaged from the keyway that meshes with the lower end of the outer casing, and the inner pipe and the down-the-hole hammer are lifted from the outer casing through the mountain rig lifting system. At this time, the outer casing functions to fix the wall of the well. After the explosive is discharged from the center of the casing to the bottom of the well, the outer casing is pulled out by the extubator to complete the drilling and medicine operation.