Technology　transfer　from　laboratory　into　practical　application　needs　to　meet　the　demands　of　economic　viability　and　operational　simplicity.　This　paper　reports　a　simple　and　convenient　strategy　to　fabricate　large-scale　and　ultrasensitive　surface-enhanced　Raman　scattering　(SERS)　substrates.　In　this　strategy,　no　toxic　chemicals　or　sophisticated　instruments　are　required　to　fabricate　the　SERS　substrates.　On　one　hand,　Ag　nanoparticles　(NPs)　with　relatively　uniform　size　were　synthesized　using　the　modified　Tollens　method,　which　employs　an　ultra-low　concentration　of　Ag　+　and　excessive　amounts　of　glucose　as　a　reducing　agent.　On　the　other　hand,　when　a　drop　of　the　colloidal　Ag　NPs　dries　on　a　horizontal　solid　surface,　the　droplet　becomes　ropy,　turns　into　a　layered　structure　under　gravity,　and　hardens.　During　evaporation,　capillary　flow　was　burdened　by　viscidity　resistance　from　the　ropy　glucose　solution.　Thus,　the　coffee-ring　effect　is　eliminated,　leading　to　a　uniform　deposition　of　Ag　NPs.　With　this　method,　flat　Ag　NPs-based　SERS　active　films　were　formed　in　array-well　plates　defined　by　hole-shaped　polydimethylsiloxane　(PDMS)　structures　bonded　on　glass　substrates,　which　were　made　for　convenient　detection.　The　strong　SERS　activity　of　these　substrates　allowed　us　to　reach　detection　limits　down　to　10　−14　M　of　Rhodamine　6　G　and　10　−10　M　of　thiram　(pesticide).　©　2018　by　the　authors.　Licensee　MDPI,　Basel,　Switzerland.