Trivalent iron (Fe³⁺) has been confirmed to exist on the highly reduced lunar surface, yet its formation mechanism remains unclear. In this study, using the electron microprobe flank method, we detected Fe³⁺ (Fe³⁺/ΣFe=0～0.31) within 15 impact glass spherules from the Chang'e-5 (CE-5) returned samples. We propose that during meteorite impacts, disproportionation of Fe²⁺ occurs within the melt, generating Fe³⁺; this same disproportionation reaction simultaneously produces metallic iron (Fe⁰), representing a significant pathway for the formation of metal iron particles within impact glass beads. The Fe³⁺/ΣFe ratio in CE-5 impact glass beads containing metallic iron particles show certain negative correlation with Na₂O, K₂O, and P₂O₅, and a positive correlation with CaO and MgO, supporting the impact process simultaneously causing the volatilization of volatile elements and the disproportionation reaction of iron. The origin of Fe³⁺ in homogeneous impact glass beads is the impact process. We observe no correlation between Fe³⁺/ΣFe and Cl as well as SO₃ in the CE-5 glass beads, suggesting that the impact process is highly complex: while disproportionation occurs, the melt simultaneously undergoes high-temperature degassing and subsequent re-incorporation of volatile elements from the impact vapor phase, which compensates partly their loss due to the impact process. This study suggests that the evaporation and reabsorption of volatile elements and the disproportionation reaction of iron occur simultaneously during the impact process, with no obvious causal relationship. Some glass beads containing metallic iron particles exhibit extremely low Fe³⁺ /ΣFe ratios, and the origin of metallic iron particles within the glass beads is complex and not solely attributable to disproportionation reactions.