Surface-enhanced　Raman　scattering　(SERS)　is　widely　used　for　trace　detection　of　substances,　and　the　key　to　this　technology　lies　in　the　preparation　of　the　substrate　material.　In　this　study,　a　composite　SERS　material　of　Au　NRs/4-MBA/PAM　was　constructed　and　characterized　to　better　immobilize　the　reference　molecule　4-mercaptobenzoic　acid　(4-MBA).　Electron　transmission　microscopy　results　demonstrated　that　the　PAM　film　helps　Au　NRs　to　pack　closely,　enhancing　the　stability　of　the　material　structure　and　reducing　the　interference　of　external　environmental　factors　on　the　response　of　4-MBA,　thus　improving　the　accuracy　of　quantitative　determination.　Comparative　experimental　results　with　the　Au　NRs/4-MBA　substrate　showed　that　the　relative　standard　deviations　(RSDs)　of　the　detection　results　for　MG　on　different　batches　of　Au　NRs/4-MBA/PAM　were　less　than　8.0%,　and　the　RSDs　of　different　points　on　the　same　material　were　less　than　10.0%,　indicating　that　the　Au　NRs/4-MBA/PAM　has　higher　uniformity,　better　reproducibility,　and　higher　sensitivity　in　detecting　malachite　green　(MG).　Applying　this　material　in　the　recovery　determination　of　fish　extract　showed　that　the　recovery　rates　of　MG　were　between　75.60%　and　83.24%.　Therefore,　the　Au　NRs/4-MBA/PAM　substrate　can　accurately　detect　and　quantify　veterinary　drug　residue　in　complex　matrices　such　as　food　tissue.