Mo-Ag-Cu-Co　films　were　fabricated　by　co-sputtering　Ag/Mo　and　Co/Cu　composite　targets.　Results　show　that　a　large　number　of　particles　grew　on　the　surface　of　Mo-Ag-Cu-Co　films　before　and　after　annealing.　The　number,　size　and　components　of　these　self-grown　particles　could　be　adjusted　and　controlled　by　changing　annealing　temperatures.　The　differences　in　diffusion　of　Ag,　Cu,　Co　and　Mo　in　Mo-Ag-Cu-Co　films　is　the　major　mechanism　of　forming　nanoparticles　with　different　components.　As　the　annealing　temperature　was　lower　than　260　°C,　the　self-formed　particles　were　Ag　single-crystal　particles　due　to　the　stronger　diffusion　ability　of　Ag　at　low　annealing　temperatures.　The　stronger　diffusion　ability　of　Cu　promotes　the　formation　of　AgCu　particles　after　annealing　at　higher　temperatures.　However,　the　number　of　Ag　atoms　is　much　more　than　that　of　Cu　atoms,　which　results　in　the　presence　of　Ag　particles.　It　was　the　first　time　that　the　monodispersed　Ag　particles　and　Ag-Cu　particles　were　obtained　on　alloy　films　by　magnetron　sputtering　without　any　template.　These　alloy　films　as　SERS　substrates　presented　excellent　SERS　performance　and　detected　the　characteristic　Raman　spectrum　of　5　×　10−12　mol/L　rhodamine　6g　(R6G)　solution,　which　could　be　ascribed　to　the　enhanced　electromagnetic　field　among　heterogeneous　particles.　©　2022　Elsevier　B.V.