Global warming caused by the emissions of greenhouse gases (N_2O,CH_4 and CO_2) is considered to be the greatest environmental problem in the world. Constructed wetlands (CWs),as a unique ecological technique,have been widely used in wastewater treatment,but their potential for greenhouse gas emissions should not be ignored. Based on in-situ monitoring in full-scale CWs,the emission fluxes of greenhouse gas including nitrous oxide (N_2O),methane (CH_4) and carbon dioxide (CO_2) in Wu River CW were determined. The results showed that Wu River CW was a source of atmosphere N_2O and CH_4. The average emission fluxes of N_2O, CH_4 and CO_2 from the CW were 14.35,35.54 and 2889.4 mg/(m~2?d),respectively. However,the emission fluxes of N_2O and CH_4 were lower than the values reported in the literature for sewage treatment plants. The emission fluxes of N_2O,CH_4 and CO_2 from the CW showed significant differences among different sampling units,and the average emission flux increased and then decreased along Wu river CW. The maximum N_2O emission flux of 51.92 mg/(m~2?d) was observed from the distribution channel,while the emission of CH_4 was found to be highest in sixth overflow weir with the flux of 182.03 mg/(m~2?d). In addition,the emission fluxes of N_2O,CH_4 and CO_2 from the CW varied seasonally,being higher in spring and summer than in fall and winter.