The effect of oxygen storage capacity on catalytic activity and stability of kappa-Ce2Zr2O8(111) during the oxy-dehydrogenation of ethylbenzene with CO2 were examined by the density functional theory calculations. Results show that four kinds of lattice oxygen O-a, O-b, O-c and O-c' existed on the kappa-Ce2Zr2O8(111) surface, compared with the lattice oxygen O on the CeO2 (111) surface, the order of catalytic activity is O-c' > O-c > O-b approximate to O-a > O. By analyzing the Hirshfeld charge distribution during the C-H bond activation, we find a positive correlation between the activity of lattice oxygen for the C-H bond activation and the charge transferred from ethylbenzene to kappa-Ce2Zr2O8 catalyst. During the reaction process, surface lattice oxygen will release from kappa-Ce2Zr2O8(111) by reaction with H to form H2O, which result in lattice oxygen loss and oxygen vacancy formation. However, the ability of oxygen vacancy formation on kappa-Ce2Zr2O8(111) is negatively correlated with its ability of CO2 activation and dissociation, and CO2 can hardly supply the lattice oxygen on the kappa-Ce2Zr2O8(111) surface with a much higher reaction barrier than C-H bond activation. Taking the O-c' of the Zr-rich termination and O-c of the Ce-rich termination as the example, the lattice oxygen from sub-surface or bulk phase can replenish the surface lattice oxygen spontaneously or just overcome a low reaction barrier of 0.26 eV, thereby maintaining the stability of the catalyst surface active site.