The continuous increase in global atmospheric CO2 concentration has profoundly affected plant physiological and ecological processes, with the response mechanisms of hyperaccumulators being particularly critical for developing effective phytoremediation strategies in contaminated soils. As a representative heavy metal hyperaccumulator, Sedum plumbizincicola has demonstrated significant potential for soil remediation, yet the regulatory effects of elevated CO2 on its growth and metal uptake efficiency remain poorly understood, particularly regarding the mediating role of soil physicochemical properties through nutrient availability pathways. This study investigated the temporal dynamics of biomass accumulation and metal uptake patterns in S. plumbizincicola grown under short-term (30-day) and long-term (90-day) Free-Air CO2 Enrichment (FACE) conditions (+200 ppm above ambient) across three distinct soil types: Perudic Luvisols (pH 5.5), Hydragric Anthrosols (pH 6.5), and Udic Cambisols (pH 7.5). The results revealed that short-term elevated CO2 exposure significantly enhanced various biomass parameters including leaf fresh weight, stem fresh weight, and plant height, with the most substantial promotion observed in Perudic Luvisols soil where leaf fresh weight increased by 2.51-fold, compared to more modest improvements in Hydragric Anthrosols soil. However, these growth stimulations diminished under prolonged CO2 exposure, with only Udic Cambisols soil maintaining statistically significant differences in biomass accumulation. Regarding metal absorption dynamics, short-term CO2 enrichment markedly improved the uptake of essential elements such as K, Ca, and Mg, particularly in Perudic Luvisols soil where K and Ca accumulation was most pronounced. However, the advantage of metal absorption was weakened after long-term high CO2 treatment, but it was still the high CO2 treatment that promoted the metal uptake. The study provides important insights into the complex interactions between atmospheric CO2 levels, soil properties, and plant physiological adaptations, offering valuable theoretical guidance for optimizing phytoremediation approaches in heavy metal-contaminated soils under future climate change scenarios. The observed temporal shifts in metal partitioning patterns further suggest potential adjustments in harvest strategies may be necessary to maximize remediation efficiency in long-term applications.