This study examined the sediment characteristics of Wolyeong Wetland through grain-size and physico-chemical analyses and assessed their spatial distribution using interpolation techniques. Grain-size analysis showed that surface sediments were primarily composed of zS and sZ fractions, with fine sand being dominant. The study area comprises four distinct wetland zones, each exhibiting unique grain-size compositions influenced by topographic location, slope-sediment supply, and hydrological conditions. Interpolation analysis further confirmed spatial heterogeneity: sand content was higher in inflow/outflow areas and peripheral slopes, while silt and clay were more abundant in flat, poorly drained terraced interiors. Chemical analyses indicated strong acidity across all sites, with no evidence of salt accumulation. Organic matter and cation exchange capacity (CEC) varied significantly among the zones, and available phosphorus was relatively high in areas with stable hydrology. The overall characteristics of the surface sediments suggest that the wetland has experienced recent environmental changes, including aridification, pedogenic processes, and vegetation expansion. This study provides essential baseline information on the development of upland paddy-field wetlands and is expected to play an important role in implementing future wetland conservation and restoration strategies.