The invention discloses a drill pipe device for mixed injection of various medicaments. The drill pipe device comprises an outer pipe, an inner pipe and a drill bit. Both the outer pipe and the inner pipe are of hollow structure and sleeved together, and a gap between the outer pipe and the inner pipe forms a first cavity. The upper portion of the outer pipe is provided with a first medicament connecting hole which is communicated with the first cavity. The inner wall of the bottom of the outer pipe is provided with a step, and the first cavity is closed by the step and the outer wall of the inner pipe together. The upper portion of the inner pipe is provided with a second medicament connecting hole which is communicated with a cavity of the inner pipe. The drill bit is connected with the outer pipe, and a second cavity is formed inside the drill bit and is communicated with the cavity of the inner pipe. Jet holes communicated with the outside are respectively formed in the side walls of the first cavity and the second cavity. The drill pipe device for injection in situ of soil and underground water realizes underground mixing of various medicaments, reduces interaction consumption before the medicaments contact with pollutants, and improves effect of in-situ repair.