Surface　enhanced　Raman　spectroscopy　(SERS)　has　been　developed　as　a　powerful　analytical　tool　in　the　fields　of　bio-medical　engineering,　environmental　monitoring　and　so　on.　Using　confocal　Raman　spectrometer,　the　SERS　substrate　can　be　used　for　spatial　analysis.　However,　reusable　and　long-life　SERS　substrate　is　urgently　needed　since　the　low　usage　cost　is　critical　to　SERS　sensor.　In　this　manuscript,　we　introduced　a　3D　Ag　nanoparticles　coated　Si　nanowire　array　SERS　substrate　fabricated　by　simple　nanofabrication.　The　enhancement　factor　of　3D　Ag　nanoparticles　coated　Si　nanowires　array　SERS　substrate　was　about　1　x　10(6)　and　its　relative　standard　deviation　is　9.85%.　The　substrate　can　be　used　for　more　than　ten　times　and　the　lifetime　was　longer　than　seventy　days.