Abstract: The combination of iron-based materials and submerged plants may make full of their respective advantages for effective control of phosphorus release from sediments. Bentonite is suitable as a supporting material to prepare low-cost adsorbent materials for phosphate removal from water. However, there are few studies on the effectiveness and mechanism of iron-modified bentonite (FeBT) combined with Vallisneria natans (V. natans) to suppress phosphorus release from sediments. We investigated the efficiency and mechanism of the combined use of FeBT and V. natans to control the release of phosphorus from sediments under different FeBT dosing modes (addition, one-time capping with a high dose, and multiple capping with low doses). For the addition and one-time capping with a high dose modes, the dosage of FeBT was 1 096 g/m². For the multiple low-dose capping mode, the dosage of each dosing was 219.2 g/m², and FeBT was added 5 times in total. The results showed that the combination of FeBT and V. natans under different dosing modes could effectively control the release of phosphorus from sediment to the overlying water, and the efficiency of FeBT combined with V. natans to control the phosphorus release from sediment was higher than that of V. natans alone. The reduction efficiencies of soluble reactive phosphorus (SRP) in the overlying water by V. natans combined with FeBT addition, one-time capping with a high dose and multiple capping with low doses were 42.7%-66.5%, 46.1%-60.4% and 30.2%-57.3%, respectively, while those by V. natans alone were 22.3%-35.3%. Furthermore, the efficiency of V. natans combined with one-time FeBT capping to prevent the release of sedimentary phosphorus into the overlying water was higher than that of V. natans combined with FeBT addition. The phosphorus in sediment could be released via the mechanisms of microorganism-driven iron (Ⅲ) and sulfate reduction, inorganic phosphorus solubilization and organic phosphorus mineralization. The immobilization of diffusion gradient in thin film (DGT)-labile phosphorus in sediment by FeBT and V. natans played a key role in the control of sedimentary phosphorus liberation into the overlying water by the combined utilization of FeBT and V. natans. In addition, the inhibition of the microorganism-driven iron (Ⅲ) and sulfate reduction by V. natans also played a vital role in the interception of phosphorus liberation from sediment into the overlying water by the combination of FeBT and V. natans. From the viewpoint of control efficiency and application convenience, the combination of one-time FeBT capping with a high dose and V. natans is a promising method for the control of phosphorus release from sediment into the overlying water.