Abstract: Bagasse-based phosphorus-doped activated carbon(PAC-900) was prepared with bagasse as carbon source, phytic acid as phosphorus source and activator, and used as electrode for the electrosorption of Cu²⁺. The pore structure, surface chemical properties and elemental composition of the samples were characterized by nitrogen adsorption-desorption isotherm, XPS and SEM-EDX. The research results showed that when the initial concentration of Cu²⁺ was 100 mg/L, the electrosorption of Cu²⁺ by PAC-900 was as high as 86.85 mg/g, which was much higher than 35.15 mg/g of undoped activated carbon(C-900). After 10 times of desorption, the adsorption capacity could still reach 45.38 mg/g. The activation of phytic acid could produce the activated carbon with the specific surface area as high as 1 671.75 m²/g, and the total pore volume and micropore volume of 1.33 cm³/g and 0.09 cm³/g, respectively, which could significantly improve its electrochemical performance and hydrophilicity. The adsorption process was mainly affected by the electric double layers adsorption and Faraday adsorption. The adsorption isotherm and adsorption kinetic process analysis showed that the adsorption process conformed to the Freundich isotherm and pseudo-second-order kinetic process, it indicated that there was not only single-layer adsorption but also multi-layer adsorption in the adsorption process; XPS and SEM-EDX analysis results showed that the P element mainly existed in the form of C—P—O, C—O—P and C—PO, and C—P was very rare, among which C—P=O contributed the most to the Faradaic adsorption of Cu²⁺.