Continuous　aggravated　surface　O-3　over　North　China　Plain　(NCP)　has　attracted　widely　public　concern.　Herein,　we　evaluated　the　effects　of　changes　in　aerosols,　precursor　emissions,　and　meteorology　on　O-3　in　summer　(June)　of　2015-2019　over　NCP　via　8　scenarios　with　WRF-Chem　model.　The　simulated　mean　MDA8　O-3　in　urban　areas　of　13　major　cities　in　NCP　increased　by　17.1%similar　to　34.8%,　which　matched　well　with　the　observations　(10.8%similar　to　33.1%).　Meanwhile,　the　model　could　faithfully　reproduce　the　changes　in　aerosol　loads,　precursors,　and　meteorological　conditions.　A　relatively-even　O-3　increase　(+1.2%similar　to+3.9%　for　24-h　O-3　and　+1.0%similar　to+3.8%　for　MDA8　O-3)　was　induced　by　PM2.5　dropping,　which　was　consistent　with　the　geographic　distribution　of　regional　PM2.5　reduction.　Meanwhile,　the　NO2　reduction　coupled　with　a　near-constant　VOCs　led　to　the　elevated　VOCs/NOx　ratios,　and　then　caused　O-3　rising　in　the　areas　under　VOCs-limited　regimes.　Therein,　the　pronounced　increases　occurred　in　Handan,　Xingtai,　Shijiazhuang,　Tangshan,　and　Langfang　(+10.7%similar　to+13.6%　for　24-h　O-3　and　+10.2%similar　to+12.2%　for　MDA8　O-3);　while　the　increases　in　other　cities　were　5.7%similar　to　10.5%　for　24-h　O-3　and　4.9%similar　to　9.2%　for　MDA8　O-3.　Besides,　the　meteorological　fluctuations　brought　about　the　more　noticeable　O-3　increases　in　northern　parts　(+12.5%similar　to+13.5%　for　24-h　O-3　and　+11.2%similar　to+12.4%　for　MDA8　O-3)　than　those　in　southern　and　central　parts　(+3.2%similar　to+9.3%　for　24-h　O-3　and　+3.7%similar　to+8.8%　for　MDA8　O-3).　The　sum　of　the　impacts　of　the　three　drivers　reached　16.7%similar　to　21.9%,　which　were　comparable　to　the　changes　of　the　observed　O-3.　Therefore,　exploring　reasonable　emissions-reduction　strategies　is　essential　for　the　ozone　pollution　mitigation　over　this　region.　(C)　2022　The　Research　Center　for　Eco-Environmental　Sciences,　Chinese　Academy　of　Sciences.　Published　by　Elsevier　B.V.