As the most sensitive and active factor, the quantity, type and diversity of soil microbe in high concentration CO2 are very important problem for ecological impact of leakage risk in CCS projects. The pot experiment in carbon dioxide artificial climate chamber was used to simulate different CO2 concentration (from concentration in normal atmosphere to 80000μmol/mol) of CCS leakage and study the effects of microbial diversity in sorghum rhizosphere soil on elevated CO2. According to comparing the DGGE electrophoresis of bacteria in sorghum rhizosphere soil under different CO2 concentration, five kinds of indicator bacteria were selected when the CO2 concentration was at 10000μmol/mol, and the soil bacteria of sorghum planting can be used as evaluation index of CO2 leakage included Brucella suis, Thiohalocapsahalophil, Burkholderia cepacia, Porphyromonas gingivicanis, and Bacteroides intestinalis. The leakage of the CCS project can be evaluated by the identification of soil bacteria of sorghum planting in the future.