One of the important factors to improve the cathode activity is the electronic structure of cathode materials in solid oxide fuel cell. In this study, we analyzed the formation energy of oxygen vacancy (VO) near the La1-xSrxCoO3-d (LSC) surface in CeO2 or gadolinium-doped CeO2 (GDC)-LSC interface model by using the density functional theory. We found the electron transfer from CeO2 to LSC region due to the difference of density of states. Stable formation energy of VO from LSC surface in CeO2-LSC interface model was obtained. The formation energy of VO in LSC near GDC interface was more stable than CeO2 interface. We clearly found that the different electronic structure in CeO2/GDCLSC interface affects the difference of VO formation in LSC.