Nano　particle　embedded　thin　film　has　great　potential　application　in　tuning　the　optical　properties　of　phase　change　material.　In　this　paper,　we　prepared　GeTe　nano　particle　embedded　Cu　composite　thin　film　(GeTe@Cu)　by　magnetic　co-sputtering　GeTe　and　Cu　targets.　High-resolution　transmission　electron　microscopy　(HR-TEM)　was　used　to　characterize　the　local　structure　of　the　composite　thin　film　and　the　GeTe　nano　particles.　It　was　found　that　the　composite　thin　film　was　constituted　of　net-like　Cu-Cu　bonds,　Ge　(Te)-Cu　bonds　as　well　as　GeTe　nano　particles.　Optical　reflectivity　of　the　composite　thin　film　was　also　measured.　Ab　initio　molecular　dynamics　(AIMD)　simulations　was　employed　to　investigate　the　forming　mechanism　of　GeTe　nano　particles　and　the　local　features　in　detail.　Simulation　results　revealed　that　Ge-Te-Ge-Te　four-fold　ring　promote　the　formation　of　GeTe　atom　cluster　and　large　amount　of　free　electrons　from　Cu　atoms　make　the　Ge-Te　bonds　stronger,　in　further　leading　to　the　formation　of　GeTe　nano　particles.　These　results　in　this　paper　paved　the　way　for　further　research　about　multi-level　optical　storage　of　nano　particles　embedded　phase　change　composite　thin　film.