Abstract: Oncomelania snails are important intermediate hosts of schistosome. The study of “snailenvironment” relations has important scientific and social value for the snails’ investigation and elimination. This study was a case research performed at Chayegang marshland near Henghu farm (Xinjian County) in the Poyang Lake basin. An incorporating model of weights of evidence and certainty factor was used to explore if the snail’s occurrences were affected by seven factors, which including three types of plant (Carex cinerascens, Miscanthus sacchariflorus, and Artemisia selengensis) coverage, soil temperature, soil humidity, soil electrical conductivity, sampling sites elevation, etc. The results showed the increasing site elevation might benefit the snails producing, and snails were very few if the soil humidity was larger than 0.35% (m3/m3), or the Carex cinerascens productions too large (>4 368 cm3/m2) or too small (<1 457 cm3/m2), or the soil electrical conductivity larger than 0.07 ms/cm. However, the snails preferred the circumstances if the Miscanthus sacchariflorus productions were larger than 2 745 cm3/m2, or the soil temperature varied between 16°C and 20°C. The model projection results showed that 87% snails mostly distributed in the 13% studied area that snails preferred. The model projected Area Under Curve (AUC) could cover 88.7% of the snail's real distribution areas, which indicated the model’s high prediction abilities, and the model can be applied to the studies of regional Oncomelania snails distribution and the environmental factors.