This paper studied the effect of 200 micromol x mol(-1) CO2 elevation on soil saccharidase activities and soil nutrient contents under rice-wheat rotation. The results showed that under both wheat and rice planting, CO2 elevation increased soil invertase activity. The elevated CO2 significantly increased soil xylanase activity at the jointing, heading and ripening stages of wheat and at the heading and ripening stages of rice, and slightly decreased soil cellulase activity. Correlation analysis showed that there was a significantly linear positive relationship between soil alkali-hydrolyzed nitrogen and soil invertase activity.