Extreme　climate　conditions,　such　as　typhoon　rainfall　events,　are　common　throughout　coastal　watersheds.　However,　despite　the　increasing　interest　in　the　impacts　of　rainstorm　patterns　on　runoff　pollution,　research　in　this　area　is　still　inadequate.　Therefore,　an　urban　water　quantity/quality　model　was　constructed　to　evaluate　the　distribution　characteristics　of　non-point　source　(NPS)　pollution　based　on　12　typhoon　rainstorm　events　that　occurred　within　the　2008-2019　period.　The　rainstorm　events　were　categorized　as　either　an　early　pattern　(EP),　middle　pattern　(MP),　or　late　pattern　(LP),　and　the　effects　of　these　patterns　on　the　NPS　pollution　of　urban　receiving　water　in　Southeast　China　were　investigated.　For　the　12　typhoon　rainstorms　under　investigation,　the　results　showed　that　97.2%　of　the　peak　concentration　time　(PCT)　of　pollution　indices　occurred　after　the　peak　rainfall　time　(PRT),　indicating　a　lag　effect　of　the　PCT,　compared　to　the　PRT.　Additionally,　it　was　observed　that　the　EP　rainstorm　events　are　more　likely　to　cause　severe　NPS　pollution　owing　to　their　association　with　the　longest　lag　time　(135-180　min)　and　the　earliest　deterioration　time　(280-303　min).　Moreover,　the　pollution　load　intensity　(PLI)　showed　a　strong　response　to　urbanized　land-use.　In　particular,　the　average　PLI　of　the　midstream　watershed　was　found　to　be　higher　than　that　of　other　watersheds.　These　results　provide　useful　information　for　the　design　of　effective　strategies　for　rainfall-runoff　pollution　mitigation　in　coastal　urban　watersheds　in　China.　(c)　2021　Elsevier　Ltd.　All　rights　reserved.