To determine the potential role of seed banks in the restoration of farmed wetlands, the seed banks of extant, restored and cultivated marsh were sampled in Sanjiang Plain, China; at the same time the effect of moisture and flooding conditions on soil seed bank also was studied by the controlled experiment. Total 60 species were identified from the seedling germination assays, 11 of which were annual and biennial, 44 perennial plants, 3 shrub species and 2 moss species. The number of species in moisture treatment(10-20 species) was greater than that in flooding treatment(2-5 species), Seed density was the greatest in the nature continuous wetland （8622±1526 seed/m2）, which increased with the increase of restoration period and declined with the increase of farm period, especially to the wetlands farmed by 20 years, the seed density was only 432±51 seed/m2. Species richness and seed density were significantly affected by restoration and farming period and water treatments, also by the interaction of restoration and water treatments. Some dominant species existed in soil seed bank of nature and restored wetland still appeared in soybean farmed field which is cultivated less than 10 years, and some hydrologic plant were present in flooding treatment, this suggested that it would readily recolonize fields after hydrologic restoration.