CH4 emission fluxes from communities of Scirpus mariqueter, Phragmites australis, Spartina alterniflora and bare mudflat in Hangzhou Bay coastal wetland were monitored in situ using the static chamber-gas chromatography method from April to September of 2013. CH4 production potentials of the 0–30 cm soil depth from the wetlands were also measured by the indoor anaerobic incubation method. The results indicated that there were remarkable seasonal variations of CH4 emission fluxes for all the studied wetlands during the observation period. Overall, the bare mudflat wetland was an absorption source of CH4, and the CH4 emission flux was higher in spring than that in summer. The other wetlands were emission sources of CH4. The CH4 emission flux was higher in summer than in spring and autumn in all the wetlands with vegetation. The average CH4 emission flux was 1.589 mg/(m2·h) for the S. alterniflora wetland, 0.722 mg/(m2·h) for the P. australis wetland, 0.218 mg/(m2·h) for the S.mariqueter wetland and –0.068 mg/(m2·h) for the bare mudflat wetland. CH4 emission flux was higher from the S. alterniflora wetland than any of the other wetlands in all the months. The average CH4 production potential from 0–30 cm soil depth from all the studied wetlands was 0.050 μg/(g·d) for the S. alterniflora wetland, 0.042 μg/(g·d) for the P. australis wetland, 0.030 μg/(g·d) for the bare mudflat wetland and 0.027 μg/(g·d) for the S.mariqueter wetland. CH4 production potential of soil from the S.alterniflora wetland was significantly higher than those of the other wetlands among all soil layers (except for 0–5 cm layer). In the bare mudflat wetland, the highest and lowest values of CH4 production potential were found in the 10–20 cm and 5–10 cm soil layers, and no obvious spatial vertical changing trend was detected in all the soil layers. Generally, the CH4 production potential in the three wetlands with vegetation decreased with soil layer depths with the largest value in the 0–5 cm soil layer. The lowest CH4 production potential was found in the 20–30 cm soil layer for the S. alterniflora wetland, the 5–10 cm soil layer for the P. australis wetland and the S. mariqueter wetland. Soil pH, soil organic carbon and total nitrogen were the important factors affecting the CH4 emission significantly in all of the wetlands studied.