The invention discloses an inner embedding tooth and outer gear coupler type double-layer drill rod, which comprises a double-layer drill rod body, wherein the double-layer drill rod body comprises an outer pipe, an inner pipe, an upper joint, a lower joint, an upper sealing ring and a lower sealing ring; the inner pipe and the outer pipe are arranged in the same axial direction; a gap is formed between the inner pipe and the outer pipe; the upper joint is arranged at the upper end of the outer pipe; the lower joint is arranged at the lower end of the outer pipe; the upper joint and the lower joint are respectively and fixedly connected with the outer pipe to form a bearing structure of the drill rod; the upper sealing ring and the lower sealing ring are respectively positioned in the upper joint and the lower joint of the drill rod and are connected with the inner pipe to form an inner layer structure of the drill rod; inner embedding teeth are arranged inside the upper joint along the circumferential direction; outer embedding teeth are arranged outside the lower joint along the circumferential direction; the outer periphery of the upper joint and the outer periphery of the lower joint are provided with outer gears in the same structures; an inner gear sleeve sleeves the outside of the outer gear of the lower joint. The drill rod provided by the invention is used as an engineering drilling machine drill rod, is used for power transmission and airlifting reverse circulation fluid transmission, and has the advantages that the bearing is safe, the fast dismounting can be realized, and the double-layer sealing is reliable.