Abstract: This study evaluated the remediation efficiency of chelator−assisted phytoremediation for copper heavy metal tailings. Taking copper tailings collected from the No. 4 tailings pond of Dexing Copper Mine in Jiangxi Province as the research material, a 90−day pot experiment using perennial ryegrass (Lolium perenne L.) was carried out. Three biodegradable chelators, namely citric acid (CA), fulvic acid (FA) and polyaspartic acid (PASP), were selected and applied to tailings via solution irrigation (CA and FA: 1–10 mmol/L; PASP: 1–10 g/L). The effects of these chelators on ryegrass growth and the translocation and accumulation of copper (Cu) and cadmium (Cd) were investigated. The results showed that all three biodegradable chelators significantly improved the physicochemical properties of copper tailings. Treatments with 1 mmol/L CA and 4 mmol/L CA achieved the optimal improvement in organic matter and cation exchange capacity (CEC), which increased by 42.88% and 91.80% respectively compared with the control group. All treatments markedly promoted ryegrass growth, with the 7 g/L PASP treatment exhibiting the most prominent effect; the aboveground and underground biomass increased by 208.28% and 79.55% relative to the control. The application of chelators effectively transformed stable residual fractions of Cu and Cd into more mobile weak acid−extractable fractions. The 7 g/L PASP treatment produced the strongest activation effect on Cd, with the content of weak acid−extractable Cd rising significantly by 103.37% versus the control. In addition, the bioconcentration factor (BCF) and translocation factor (TF) of Cu in ryegrass reached maximum values under the 4 mmol/L CA treatment, which were significantly elevated by 92.24% and 41.67% compared with the control, respectively. The 7 g/L PASP treatment was most conducive to Cd accumulation and translocation in ryegrass, with its BCF and TF significantly increasing by 18.00% and 106.90% relative to the control. Principal component analysis (PCA), which comprehensively evaluated core indicators including tailings physicochemical properties, available heavy metal contents and heavy metal fraction distributions, demonstrated that 4 mmol/L CA and 7 g/L PASP possessed the optimal application potential for remediating Cu and Cd contamination in copper tailings, respectively. The findings of this study can provide scientific references for efficient phytoextraction and ecological restoration of heavy metal pollution in copper sulfide mining areas.