Ge/Sb　atomic　intermixing　in　interfacial　cationic　layers　is　a　common　phenomenon　for　GeTe-Sb2Te3　superlattice　(GST-SL)　used　in　memory　devices.　In　this　paper,　we　explored　the　effect　of　Ge/Sb　intermixing　on　the　phase　change　behavior　of　GST-SL　upon　the　heating-quenching　procedure.　Four　interfacial　intermixing　models　of　Kooi,　Ferro,　Petrov　and　inverted　Petrov　with　different　Ge/Sb　intermixing　ratios　(25/75,　50/50　and　75/25)　were　developed　based　on　the　ab　initio　molecular　dynamics.　The　structural　evolution　indicated　that　the　Ge/Sb　interfacial　intermixing　could　facilitate　the　structure　changes　especially　for　50/50　Ge/Sb　intermixed　models.　When　quenching　from　1500　K,　more　4-fold　Ge-centered　octahedrons　were　produced　than　tetrahedrons,　and　the　electron　localization　function　further　proved　that　the　distorted　of　Ge(Sb)-centered　6-fold　octahedrons　were　caused　by　the　asymmetrical　interactions　of　Ge-Ge/Sb　and　Ge-Te.　A　relatively　large　Te　p　orbital　contribution　in　coexisted　Ge/Te　layer　led　to　a　narrower　bandgap.　In　addition,　different　Ge/Sb　atom　intermixed　ratio　which　affected　the　electronic　local　structure,　led　to　the　discrepancy　in　the　initial　atom　movement　of　Sb　or　Ge　movement　near　the　gap.　The　present　studies　enrich　the　understanding　of　Ge/Sb　interfacial　atomic　intermixing　effects　in　GST-SL　structural　changes.