▎ 摘　　要

We have studied the exciton effects in armchair graphene nanoribbons systematically, using the nonorthogonal tight-binding model supplement by the long-range Coulomb interactions. It is found from our calculations that the excitation energies, the exciton binding energies and the exciton wave function sizes of the E (11) and E (22) excitons all exhibit oscillation as a function of the ribbon width. And there is a phase shift of pi between the oscillation of the E (11) and E (22) excitons.