The grazing characteristics of Radix swinhoei on different kinds of submerged plants were studied. According to the grazing experiments of three sizes of large (0. 78 g/ind), medium (0. 28 g/ind), small (0. 06 g/ind) and different densities of low(40 ind/L), medium(80 ind/L), high(120 ind/L) of Radix swinhoei, grazing rate and selectivity of three submerged plants of Elodea nuttallii, Cabomba caroliniana, and Vallisneria natans by R. swinhoei were studied. The results showed that:The total grazing rate of R. swinhoei was inversely proportional to the snail size; The small-sized snail has the highest total grazing rate for submersed plants, reaching (219.66±47.17) mg/(g·d), and the medium-sized snail is (47.53±9.08) mg/(g·d); The grazing rate of large size is the lowest with only (20. 37±14. 60) mg/(g·d). Different densities had no significant difference for the whole grazing rate on submerged plants. The preference of R. swinhoei for the three submerged plants does not change with the size. R. swinhoei with different sizes will preferentially graze E. nuttallii and V. natans, and do not like C. caroliniana. R. swinhoei with the same size and different density will preferentially graze V. natans. The research results are of great significance for rational allocation of aquatic animals, improvement of aquatic ecosystems and enhancement of ecosystem stability in restoration projects.