By selecting the leaf (LSI) and stem (SSI) homogeneous suspension of Iva xanthi folia, we investigated the use of the biomass of this plant as a biosorbent to remove Cu ²⁺ from aqueous solution by examining the effects of pH, adsorption time and concentration of Cu ²⁺ on adsorption efficiency. Optimal adsorption occurred with pH 6.0 to 7.0; The adsorption reached equilibrium in 30 min, and I. xanthifolia biomass can be used to treat Cu ²⁺ polluted water at concentrations < 800 mg·L^-1. By using Langmuir and Freundlich equations to model the adsorption processes, we deduced the saturation adsorption capacity of LSI and SSI for Cu ²⁺ as 28.68 and 13.06 mg·g^-1, respectively. FTIR spectra and XRD were used to analyze the functional groups in I. xanthi folia to determine what changed before and after the Cu ²⁺ adsorption effect on LSI and SSI. Cellulose and amylase are the primary adsorption materials of I. xanthifolia, and possibly the main adsorption functional groups were amido, hydroxy and carbonyl. I. xanthifolia could be a new type of heavy-metal adsorption material.