Currently, coupling noble metal species with rare-earth cations (REI) in amorphous materials has attracted persistent attention, owing to the significant rise in the emission intensity and nonlinear optical response, which allow various potential applications in photoelectric fields. However, the primary investigations are focused on Au- and Ag-doped systems, and there are few systematic reports concerning the interaction between REI and the different oxidation states of copper so far. Herein, we demonstrated the evolution of copper oxidation valences from Cu2+ to Cu+, and then to Cu-0 (Cu NPs), and the corresponding effects on Tb3+ emissions in borate glasses were systematically investigated by modifying glass structure and Sn2+/Si codoping. With increasing the ratio of B2O3 to Li2O, enhancement of reduction efficiency of Cu2+ to Cu+ was observed. Impressively, the ns(2)-type Sn2+ emission centers not only generate efficient sensitizers for Tb3+ but also lead to efficient reduction in Cu2+ to Cu+. Based on absorption/transmittance, photoluminescence excitation/emission, and time-resolved decay spectra, the interplay mechanisms between Tb3+ and the different valences of copper were discussed in detail.