The　uneven　distribution　of　metal　nanoparticles　is　a　vital　influencing　factor　in　the　poor　uniformity　of　surface-enhanced　Raman　scattering　(SERS)　substrates,　which　is　a　challenge　in　SERS　quantitative　analysis.　Recent　reports　showed　that　the　reproducibility　of　a　nonuniform　SERS　substrate　can　be　effectively　improved　by　the　use　of　an　internal　standard　(IS).　However,　most　of　these　approaches　require　the　investment　of　time　for　precise　regulation,　and　those　approaches　based　on　the　addition　of　an　IS　are　specific　to　a　certain　substrate.　In　this　work,　we　proposed　a　simple,　rapid　and　universal　method　to　incorporate　an　IS　into　a　SERS　substrate　for　improving　the　reproducibility　of　Raman　signals　based　on　the　systematic　evaluation　of　the　influencing　factors　of　the　competitive　adsorption　between　the　IS　and　the　target　analytes.　Following　the　proposed　pressure　drop-coating　(PDC)　method,　an　IS-modified　gold　nanobipyramids　(Au　NBPs)/anodic　aluminum　oxide　(AAO)　SERS　substrate　was　fabricated　within　1　min,　showing　high　reproducibility　of　Raman　signals.　In　addition,　the　IS-modified　Au　NBPs/AAO　SERS　substrate　was　successfully　applied　to　analyze　thiram　in　freshly　squeezed　apple　juice　and　the　result　showed　a　stable　Raman　signal　with　a　relative　standard　deviation　of　less　than　6.00%.　What　is　more,　three　different　commercial　SERS　chips　were　modified　with　an　IS　molecule　using　the　PDC　method.　Compared　to　the　traditional　SERS　chips,　the　Raman　signal　reproducibility　of　the　functionalized　SERS　chips　was　improved　significantly.　Since　the　addition　of　an　IS　is　not　based　on　a　certain　substrate,　the　proposed　approach　could　be　useful　for　all　the　researchers　working　in　the　field　of　SERS.　This　journal　is　©　The　Royal　Society　of　Chemistry.