This study aims to investigate the survival of a model environmental bacteria (i.e. Shewanella oneidensis MR-1) influenced by CO2 leakage from geo-sequestration sites. When CO2 partial pressure was raised to 1.5 psi, the growth of S. oneidensis MR-1 was significantly reduced compared to the control experiments (doubling time extended from 1.3 to 11.8 hr). When the CO2 pressure was over 15 psi, the growth of S. oneidensis MR-1 was fully stopped, and SEM / AFM images revealed significant cell collapse and cellular content release. However, the presence of calcite could alleviate CO2 stress to bacterial cells, possibly due to pH control by releasing calcium in the system. A two-parameter mathematical model was developed to describe the bacterial survival under the CO2 effect. This preliminary study provides useful information for understanding the potential ecological impact near CO2 geo-sequestration Sites.