Submerged plants and snails both are important components of aquatic ecosystems. Their relationships with herbivory also play an important role on the aquatic food web, and different sediment types may affect the growth of them and change the defensive strategy of submerged plant against snail herbivory. By taking Vallisneria spiralis and Radix auricularia as the research object in this research, we studied the effects of sediment types, snail herbivory on the growth submerged plants and the defensive strategies change, and also studied the effects of sediment types on snail growth and physiological characteristics. Our results showed that snail herbivory and sediment types have a significant impact on the growth and elemental characteristics of V. spiralis. In the presence of snail herbivory, the relative growth rate of V. spiralis in mixture and sand sediment both were significantly reduced. The shoot biomass of V. spiralis in mixture, sand and mud sediment were decreased by 67.74%, 58.58% and 17.84%, respectively, and the root:shoot biomass ratio increased by 177.51%, 217.23% and 1.44%, respectively. The leaves number of V. spiralis in mixture was significantly reduced with snail herbivory. Under different sediment types, the herbivory had no significant effect on the total carbon content of V. spiralis. However, the snail herbivory significantly reduced the total nitrogen content of V. spiralis, and C/N increased significantly in mud and mixture sediment. The total phenols content of V. spiralis was significantly reduced in sand sediment. The sediment types had no significant effect on the morphological characteristics (except for shell width), growth and element content of R. auricularia. In conclusion, the sediment types influenced on the snail herbivory and the defense strategy of V. spiralis in some extent, but had no effect on the growth and elemental characteristics of R. auricularia. This study can provide basic data support for the research of herbivory theory, and also provide reference for submerged vegetation restoration and aquatic ecosystem stability. However, the long-term effects of sediment types on submerged plants, snails, and their relationships with herbivory need to be further studied.