Research of ecosystem respiration (Reco) in wetland ecosystem is critical for estimating wetland ecosystem carbon balance. Continuous eddy covariance measurements were made in a poplar plantation located in the riparian wetland of middle reaches of Yangtze River. Reco was estimated and analyzed for its regulatory factors based on data from 2005-07-23 through 2007-12-15. We found that: (1) Reco had an obvious seasonal fluctuation with peak Reco in August and minimum in January. The seasonal change was affected by canopy air temperature, soil temperature, and soil water content, with canopy air temperature as the most important factor; (2) exponential equations (e.g., Van′t Hoff, Arrhenius and Lyold-Talor) were effective in modeling Reco with canopy air temperature and soil water content; (3) Reco in 2006 and 2007 were 10747 and 1127.0 gC m-2 a-1, respectively, based on the multiplicative model. These estimates were closed to forest sites in subtropical and temperate zones.