The changes of snail situation in the marshlands and the economic benefit of planting were investigated after planning sesame on marshlands above 16 meters' elevation in Poyang Lake at drought period in autumn and by comparing three groups, i.e. planting sesame alone, planting sesame plus fertilizing "Rong Bao" (a brand of one fertilizer), and no planting. Results showed that the yields in the groups of planting sesame alone and planting plus fertilizing were 15.5 kg and 19.5 kg per 667 m2, respectively, with the output increasing by 25.81% in the fertilizer group. The net incomes of the two groups of planting sesame were 56.5 Yuan and -36.0 Yuan per 667 m2, respectively. One year after the planting, the living snail densities of the three groups were decreased by 97.86%, 100% and 47.62%, respectively. It is suggested that planting sesame on marshlands with snails in Poyang Lake region has a preferable economic benefit and snail control effect.