Spent coffee ground (SCG), a byproduct from the soluble coffee industry, is usually discarded as waste. Thereutilization of SCG for the removal of toxic heavy metal ions is a novel research direction. Until recently, the molecularadsorption and reduction mechanism of Cr(VI) on SCG was barely investigated. In this study, SCG was used forthe efficient removal of Cr(VI) at a concentration range of 2-100mg/L, with a maximum Cr(VI) uptake up to 36.2mg/g. Structural characterization and ATR-FTIR analysis indicated that SCG possessed abundant surface O and N- containingfunctional groups. The corresponding adsorption and reduction effects on the Cr(VI) removal were investigatedby the carboxyl and hydroxyl groups elimination experiments and ATR-FTIR characterization, respectively. Theresults revealed that HCrO4 ions were preliminarily adsorbed on SCG surfaced-COOH/-OH/-NH by the formation ofhydrogen bond (SCG surfaced-COOH/-OH/-NH···HCrO4), and quickly reduced to Cr(III) by the electron denoted byphenolic compounds, and then in-situ immobilized on the surface of SCG. The effect of Cr(VI) concentration, coexistingions, and humic acid was systematically studied to optimize the removal of Cr(VI) wastewater. Column experimentsprovided a new substitution to restore the Cr(VI)-containing groundwater for the permeable reactive barrierapplication. Thus, the proposed study uncovered the intrinsic Cr(VI) removal mechanism at the molecular level andexplored the application of SCG for the efficient removal of Cr(VI).