Effect of elevated surface O₃ concentration（~70 nmol mol^-1） on functional diversity of soil microbial communities in paddy field under the rice/wheat rotation system was investigated in 2009 and 2010 through determination of water-soluble organic carbon (WSOC) content and BIOLOG index, by making use of the O₃-FACE ( Free-Air ozone Concentration Enrichment) platform of China. Results show that with O₃ concentration elevated, both WSOC content, and AWCD (Average Well Colour Development ) tended to decrease. Diversity indexes determined in the two years indicate that elevated O₃ concentration did not have much effect on, Shannon, Simpson and McIntosh indices. PCA results in 2010 show that elevation of O₃ concentration affected the edaphon’s ability of utilizing substrates of some specific carbon sources. The findings of the experiment suggest that under elevated O₃ concentration (~70 nmol mol^-1), functional diversity of soil microbes was significantly increased in rice field.