Lattice vibration of one-dimensional copolymer chains was studied and the dispersion relation was obtained numerically. The character of the vibration modes was recognized. It was found that the interface modes may appear if the homopolymer blocks have a strong interaction with each other, whose frequencies lie in the band gap between the acoustic and optical branches or between two optical branches. The character of the organic quantum well or superlattice of a copolymer chain was discussed from the view point of vibration modes.