Tropospheric　ozone　(O3),　which　is　one　of　the　main　pollutants　impeding　air　quality　compliance,　has　received　considerable　attention　in　China.　As　maritime　transportation　continues　to　expand,　the　effect　of　ship　emissions　on　air　quality　is　becoming　increasingly　important.　In　this　study,　the　Weather　Research　and　Forecast　model　(WRF),　the　Community　Multiscale　Air　Quality　model　(CMAQ),　and　the　integrated　process　rate　(IPR)　module　provided　in　the　CMAQ　are　applied　to　evaluate　the　impacts　of　ship　emissions　on　O3　concentration　at　a　national　scale　in　China,　including　the　spatiotemporal　characteristics　and　influencing　pathways.　Ship　emissions　can　increase　or　decrease　O3　concentrations,　with　varying　effects　in　different　seasons　and　regions.　In　the　winter,　spring,　and　fall,　ship　emissions　were　predicted　to　decrease　O3　concentrations　in　most　areas,　whereas　in　the　summer,　they　increase　the　O3　concentration,　even　in　regions　far　away　from　the　coastline,　thus　adversely　affecting　the　Yangtze　River　Delta　(YRD)　and　Pearl　River　Delta　(YRD).　Additionally,　owing　to　differences　in　the　emissions　of　volatile　organic　compounds　and　nitrogen　oxides,　the　northern　and　southern　regions　of　the　YRD　respond　differently　to　ship　emissions.　Additionally,　the　influence　of　ship　emissions　on　the　diurnal　variation　of　O3　in　the　summer　was　investigated,　where　significant　differences　were　indicated　between　cities.　The　IPR　was　used　to　investigate　the　individual　processes　contributing　to　changes　in　the　O3　concentration　caused　by　ship　emissions.　The　transport　process　appears　to　be　the　primary　contributor　to　O3　production,　whereas　chemistry　and　dry　deposition　played　key　roles　in　O3　loss.　This　study　provides　an　in-depth　insight　into　the　impacts　of　ship　emissions　on　O3　in　China,　which　can　facilitate　the　formulation　of　corresponding　environmental　policies.　©　2023