Abstract: Vegetation harvest in winter from coastal wetlands has become increasingly popular in eastern China, because of the need for eutrophication control and the fact that the plant can be freely used as papermaking raw materials. However, insufficient investigation has been conducted to evaluate the effects of the disturbance on emissions of greenhouse gases in sediments. Field plot experiments were arranged in vegetation zones of Phragmites australis, Spartina alterniflora, the intergrowth area of the two species and mudflat in a typical coastal wetland, Chongming Dongtan, in the Yangtze River Delta of China. Each plot was treated as half-and-half into two subplots, managing with and without vegetation harvest in winter. Sediment samples were taken from all subplots at 0,0, 30, and 60 days after harvesting. The sediment cores were incubated at 30 ℃ for 60 days, measuring CO₂ and N₂O fluxes over time to determine whether the seasonal vegetation harvest substantially affected emissions of the two greenhouse gases in sediments or not. The results showed that harvesting vegetation from the S. alterniflora zone and the intergrowth area of P. australis and S. alterniflora did not enhance CO₂ emissions in sediments, while harvesting P. australis possibly enhanced N₂O emissions (P<0.05). This indicated that the effects of vegetation harvest on CO₂ and N₂O emissions in the sediments largely depended on vegetation types. The total effluxes of CO₂ in the S. alterniflora zone and the intergrowth areas were 12%-57% and 17%-43% higher than those in the P. australis zone, respectively. However, N₂O emissions in the P. australis zone were 11%-81% and 8%-95% higher than those in the S. alterniflora zone and the intergrowth areas, respectively. This suggested that respiration losses of carbon in sediments in the S. alterniflora zone and the intergrowth areas were found to be much higher than those in the P. australis zone. In contrast, N₂O emissions in the P. australis zone were clearly greater than those in the S. alterniflora zone and the intergrowth areas. In addition, the total amounts of N₂O emissions across the four zones were 0.1-0.4 mg/kg in the 60-day incubation, while the emissions of CO₂ reached up to 1024-2645 mg/kg. Therefore, seasonal vegetation harvest in the coastal wetlands hardly increases the contribution of N₂O to the greenhouse effect. Selectively harvesting S. alterniflora potentially reduces the respiration loss of carbon in sediments. This implies that the short-term vegetation harvest in coastal wetlands is environmentally cost-effective.