A waveguide of a 3D interconnection structure and an optical data bus system of a 3D interconnection structure using the same are provided. The waveguide includes a main waveguide which is formed in a predetermined direction and at least one branch waveguide which connects to the main waveguide to form a predetermined angle, wherein the at least one branch waveguide branches an optical signal, which is propagated in the main waveguide, at a predetermined rate.