We　report　here　a　simple　and　innovative　method　to　prepare　large-scale　silver　nanoparticle　films　based　on　the　controlled　coffee　ring　effect.　It　is　demonstrated　that　the　films　can　be　used　as　surface-enhanced　Raman　scattering　probes　to　detect　low-concentration　medicines.　Silver　nanoparticles　with　the　average　size　about　70　nm　were　prepared　by　reduction　of　silver　nitride.　In　our　experiment,　the　coffee　ring　effect　was　controlled　by　tilting　the　substrates　during　the　deposition　of　silver　nanoparticle　films.　Silver　nanoparticle　films　were　spontaneously　formed　on　the　surface　of　silicon　substrates　at　the　temperatures　about　50A　degrees　C　based　on　the　solvent　evaporation　and　the　coffee　ring　effect.　The　microstructure　of　the　films　was　investigated　using　the　scanning　electron　microscope　and　atomic　force　microscope.　The　surface　roughness　of　the　films　is　found　as　small　as　20　nm.　Then,　the　films　were　exposed　to　aqueous　solutions　of　medicine　at　different　concentrations.　A　comparison　with　a　Raman　spectra　measured　with　a　conventional　Raman　spectrometer　showed　that　the　Raman　signal　can　be　detected　in　the　solution　with　concentrations　as　low　as　1　x　10(-5)　M,　and　the　enhancement　factor　achieved　by　the　silver　nanoparticle　film　can　at　least　reach　to　1.08　x　10(4).　Our　experimental　results　indicate　that　this　technique　is　promising　in　the　production　of　large-scale　silver　nanoparticle　films　for　the　surface-enhanced　Raman　scattering.　These　may　be　utilized　in　biochemical　and　trace　analytical　applications.