After comparing the removal effect of Vallisneria natans on Cu²⁺, Zn²⁺, Cd²⁺, Pb²⁺, and the responses of chlorophyll fluorescence parameters at low, medium and high concentration levels, our results showed that:(1) Among the four heavy metals, Vallisneria natans has the best removal effect on Cu²⁺ and the highest absorption of Zn²⁺. The maximum absorption of Cu²⁺, Zn²⁺,Cd²⁺ and Pb²⁺ by bitter grass were 4.21, 25.3, 0.231 and 0.509 μg/g respectively, the attenuation ratio of the medium mass concentration group of Cu²⁺ was the highest (47.33%),and that of the low mass concentration group of Zn²⁺, Cd²⁺, Pb²⁺ was the highest (33.13%, 29.2%, 45.7%);(2) Under heavy metal stress, the chlorophyll a content of Vallisneria natans in the Cu²⁺ and Zn²⁺ high mass concentration groups decreased less than that in the Cd²⁺ and Pb²⁺ high mass concentration groups, and the order of the decrease in chlorophyll b content was Zn²⁺ >Cu²⁺ >Cd²⁺ >Pb²⁺, and the high mass concentration group decreased significantly. (3) The maximum photochemical efficiency (F_v/F_m) and potential photochemical efficiency (F_v/F₀) of Vallisneria natans increased in different degrees under Cu²⁺ and Zn²⁺ stress, but decreased significantly under Cd²⁺ and Pb²⁺ stress. The photochemical quenching coefficient (Q_p), non-photochemical quenching efficiency (Q_n) and the quantum yield of regulatory energy dissipation (Y_NPQ) all decreased with the increase of heavy metal mass concentration, in which the decrease of Q_p in Zn²⁺, Cu²⁺, Cd²⁺, Pb²⁺ mass concentration groups decreased in turn, while the effective quantum yield (Y_Ⅱ) increased with the increase of heavy metal mass concentration. In general, Vallisneria natans is more suitable for removing Cu²⁺ and Zn²⁺ in water. The research results may lay a foundation for the ecological restoration of heavy metal polluted rivers.