Abstract: Pyrolysis is a highly promising and efficient method for processing retired photovoltaic cells. The ethylene-vinyl acetate (EVA) polymer adhesive within cells undergoes decomposition during pyrolysis. This study employs density functional theory (DFT) to construct an EVA model featuring a backbone with six carbon atoms, combining rate constant analysis to elucidate the pyrolysis mechanism of EVA. In the initial stage, EVA primarily undergoes the ?homolytic cleavage of the backbone C–C bonds? and ?deacetylation reactions initiated by hydrogen transfer?, producing acetic acid and hydrocarbon radicals. After acetyl groups removing from the backbone, the long-chain hydrocarbon intermediates generated by pyrolysis undergo the ?C–C bond scission via homolytic cleavage and intramolecular hydrogen transfer?. This process yields short-chain hydrocarbons such as CH?, ethylene, 1-butene, and free radicals. Some intermediates further participate in ?Diels-Alder and substitution reactions? to form aromatic compounds like benzoic acid. Subsequently, acetic acid continues to decompose via hydrogen transfer reactions, generating CO? and CH?.