The latest researches on the effects of elevated atmospheric CO2 on the exchanges of trace gases (e.g., CO2, CH4 and N2O) between the atmosphere and ecosystems were reviewed. The techniques and methods involved in the researches were introduced firstly. Then the review mainly focused upon the results from those studies using the open-top-chamber (OTC) methods and the free-air carbon dioxide enrichment (FACE) system. Generally, elevated atmospheric CO2 may stimulate biomass accumulation, and enlarge C/N ratio in plant tissue so as to reduce the decomposition of organic matter. This action could increase CO2 sequestration in terrestrial ecosystems. Elevated atmospheric CO2 could impact on methanogenic bacteria and CH4 emissions. An increase in CH4 emissions from wetland may appear. The argument among the responses of N2O emissions to elevated CO2, however, was inconsistent. So far, no study on other trace gases was reported. More efforts should be taken in the research on the effects of elevated atmospheric CO2 on the exchange of trace gases.