We investigate the dissociation dynamics of core-excited O2 molecules using a high-resolution energy-resolved electron-ion coincidence experimental setup.The excited cationic states with two valence holes and one Rydberg electron are created after spectator Auger decay induced by O 1s →(4Σ-u)3sσ core excitation in O2.From the energy correlation between the kinetic energy of the Auger electron and the ion kinetic energy release,we distinguish several dissociation channels.Rather complex dissociation channels of the spectator Auger final states are disclosed,which can be explained by the increased number of the crossing point due to the existence of Rydberg electron.The quantum system will evolve into different dissociation limits at each crossing point between the potential energy curves.