Enhanced oil reeovery with CO2 (CO2-EOR) is considered as a cost effective way for carbon capture and storage.However, due to the complexity of geological structure in underground reservoirs, long-term leakage is possible.A case study of CO2-EOR has been conducted at Citronelle, Alabama in USA.The total of 8,036-ton of CO2 was injected and some leakages via production were identified by isotopic analysis in May 2010.In this study, remote sensing data of CO2 and CH4 concentrations,and aerosol optical depth (AOD) at a large scale were used to monitor emissions to atmosphere at the study site.Based on the dynamics of monthly CO2 and CH4 concentrations in atmosphere at the study site and surrounding areas, some possible abnormal values were identified at different time scales.The annual average of ratios between CO2 concentration and CH4 concentration reaehed the highest value in 2009.The annual average of monthly AOD was relative lower at the study site than the surrounding areas, but it became higher after 2007.Remote sensing data could be used to monitor and evaluate emissions from CO2-EOR at a large scale and provide helpful information for ecologieal assessment of CO2-EOR.