The effect of elevated surface O3 concentration（≈ 70 nmol/mol） on soil microbial functional diversity was investigated by determining soil microbial biomass carbon (MBC), dehydrogenase activity and invertase activity in China O3-FACE ( free-air ozone concentration enrichment) field based on a rice/wheat rotation system in 2009 and 2010. The results showed that the soil MBC tended to increase, and the activities of dehydrogenase and invertase significant enhanced (P<0.05) under the elevated O3 concentration. The increase in the utilization of carbon source and the microbial biomass will improve the degradation and cycle of organic carbon which enhance the emission of green house gas with a certain period under the condition of elevated O3 concentration.