Abstract: Characteristics of ecosystem carbon exchange and its impact factors in Artemisia ordosica shrubland in 2011(low precipitation) and 2012(high precipitation), Ordos Plateau, were studied using eddy covariance methods. The results showed that the diurnal dynamics of ecosystem carbon exchange could be expressed as singlepeak and doublepeak curves in the two different precipitation years. In 2011, three carbon absorption peaks and three carbon release peaks of ecosystem carbon exchange presented in the growing season. In 2012, four carbon absorption peaks and one carbon release peak appeared in the growing season. The A. ordosica shrubland was a net carbon sink from June to September and a carbon source in October in 2011. In 2012, A. ordosica shrubland was a net carbon sink in the whole growing season. The amount of carbon fixed by A. ordosica shrubland in the growing season in 2012 was 268.90 mg CO₂·m^-2·s^-1  higher than that in 2011. The ecosystem carbon exchange of A. ordosica shrubland was controlled by PAR (photosynthetically active radiation) on the day scale, and  affected by both abiotic (precipitation and soil water content) and biotic (aboveground net primary productivity) factors on the growing season scale.