The　discharge　of　acidic　wastewater　poses　a　significant　environmental　challenge　to　sustainable　industrial　development,　underscoring　the　urgent　need　for　advanced　technologies　capable　of　efficient　water　and　acid　resource　recovery.　Nanofiltration　(NF)　as　a　promising　approach,　yet　the　high-performance　acid-resistant　membrane　is　still　in　great　demand.　Herein,　an　acid-resistant　NF　membrane　is　designed　and　prepared　by　generating　sulfonamide　groups　from　the　large-size　triazine　amine　monomer　and　1,3,6-naphthalene　trisulfonyl　trichloride　(NTSC).　Specifically,　the　acid-resistant　nanofiltration　membrane　was　fabricated　via　interfacial　polymerization　using　the　synthesized　N-2,N-4,N-6-tris(2-aminoethyl)-1,3,5-triazine-2,4,6-triamine　(TET)　with　NTSC　and　1,3,5-benzenetricarbonyl　trichloride　(TMC).　Owing　to　the　reduced　density　of　amide　bonds　in　the　separation　layer　caused　by　the　increased　spatial　dimensions　of　the　TET　monomer　and　the　formation　of　sulfonamide　structures,　the　resulting　membrane　demonstrated　high　stability　under　harsh　acidic　condition,　maintaining　97.3　%　of　rejection　for　Na2SO4　along　with　4.87　LMH.bar(-1)　of　water　permeability,　even　after　prolonged　exposure　to　15　%　H2SO4　for　80　days.　This　work　introduces　a　novel　strategy　to　enhance　the　membrane　stability　in　acid　environment,　offering　a　promising　candidate　for　practical　applications　in　acidic　wastewater　treatment.