The invention discloses a tubular busbar, especially a copper aluminum interface alloy composite conductor internal wave tube used in a tubular bus duct, and belongs to the technical field of power distribution equipment. The copper aluminum interface alloy composite conductor internal wave tube comprises a main conductor aluminum pipe and a copper pipe sleeved at the outer wall of the aluminum pipe; and the inner wall of the aluminum pipe is provided with a plurality of convex-concave wavelike convex strips. The copper aluminum interface alloy composite conductor internal wave tube used in the tubular bus duct provided by the invention greatly increases the conductivity of the inner surface of the conductor, reduces the temperature rise during current carrying capacity, and has a good heat dissipation and convection function, thereby ensuring the long load operation of the safety production of a large current tubular busbar.