Background:　ship　emissions　have　an　adverse　effect　on　air　quality　in　coastal　regions,　and　this　effect　can　be　exacerbated　by　onshore　winds.　Objectives　and　methods:　to　investigate　the　impact　of　ship　emissions　on　air　pollutant　concentrations　during　the　onshore　wind　period　in　a　low-latitude　region　in　China,　this　study　applied　the　WRF/Chem　model　to　simulate　the　contribution　of　ship　emissions　to　PM2.5　and　O-3　by　＂zero-out＂　in　2018,　in　the　Guangdong-Hong　Kong-Macao　Greater　Bay　Area　(GBA).　Results/findings:　results　show　that　the　onshore　winds　facilitated　the　transport　of　ship-emitted　pollutants　to　inland　areas,　causing　the　contribution　of　ship　emissions　to　PM2.5　exceeding　4　mu　g/m(3)　to　areas　north　of　Guangzhou　in　April　and　west　of　the　GBA　in　October.　The　impact　of　onshore　winds　on　the　ship　contribution　to　the　O-3　concentration　shows　a　bidirectional　trend　both　spatially　and　monthly.　The　onshore　winds　raised　the　ship　contribution　to　O-3　concentrations　in　April　by　1.54　mu　g/m(3),　while　exacerbated　the　decreasing　contribution　in　other　months.　In　VOC-sensitive　cities　such　as　Foshan,　onshore　winds　exacerbated　the　negative　contribution　of　ship　emissions　to　O-3　concentrations;　while　in　NOx-sensitive　cities　such　as　Huizhou,　they　enhanced　the　contribution　of　ship-induced　O-3.　Novelty/Improvement:　this　paper　fills　a　gap　in　the　study　of　pollutants　transportation　characteristics　from　ship　emissions　under　the　influence　of　onshore　winds　in　the　GBA.　Our　results　demonstrate　the　importance　of　considering　meteorological　conditions　and　atmospheric　chemical　mechanisms　regarding　the　coastal　air　pollution　prevention　caused　by　ship　emissions.