Electronic states of lithium ion (Li+) interacting with a chlorinated graphene surface (Cl- graphene) have been investigated by means of hybrid density functional theory (DFT) to elucidate the effect of chlorination of graphene on the diffusion of lithium ion. Also, direct molecular orbital-molecular dynamics (MO-MD) calculation [H. Tachikawa, J. Phys. Chem. C, 112 (2008) 10193] was applied to diffusion processes of the Li+ ion on Cl- graphene. The potential barrier height for movement of Li+ was estimated to be 2.95 kcal/mol on Cl- graphene. The direct MO-MD calculations showed that the Li+ ion diffuses freely on bulk and edge region of Cl- graphene at 300 K. The nature of the interaction between Li+ and Cl- graphene was discussed on the basis of theoretical results.