Conventional cotton bleaching is highly energy-intensive, water-dependent, and textile-damaging. The technologies currently used to achieve low-temperature bleaching always include a conflict between effectiveness and cost. This study represents an economically efficient process for cotton bleaching with H2O2 at low temperature. A novel system that couples Cu2+ with HCO3 −, has been developed to activate cotton bleaching. Factors that influence the bleaching performance were investigated, including the bleaching temperature and initial concentrations of the components (H2O2, NaHCO3 and Cu2+). The experimental results indicated that the Cu2+-HCO3 −/H2O2 system had a lower operating cost and higher bleaching efficiency than conventional and TAED-activated systems. Additionally, the bleaching bath exhibited excellent reusability, further strengthening its feasibility for industrial applications. The results of HO• scavenging and Cu2+ monitoring experiments implied that the bleaching active species might be the Cu(III) species rather than HO•. This novel system provides a simple, effective, and cost-efficient method for practical bleaching.