The static theory shows that the bond structure of C 6 0 is distorted by charge transfer and the distortion of C 6 0 - is localized in the equatorial area to form a string polaron with symmetry D 5 d . This paper further studies the, dynamical process of forming the polaron. The time-dependence of the bond distortion demonstrates the evolution of the lattice relaxation from the symmetry I h to D 5 d , and the calculated relaxation time agrees with the experiment.