Abstract. With the Two Phases of Clean Air Actions in China, the shipping sector has emerged as a significant source with substantial emission reduction potential compared to land-based anthropogenic sectors. Therefore, understanding the contribution of shipping emissions to ozone (O₃) pollution is therefore essential for advancing China’s air pollution control efforts. In this study, a coupled framework including a chemical transport model with machine learning techniques was developed to systematically investigate the interannual and seasonal impacts of shipping emissions on O₃ concentrations across China during the period from 2016 to 2020, and explore mechanisms of shipping emissions influence O₃ formation. Results indicate that shipping emissions increases O₃ concentrations by a five-year average of 3.5 ppb nationwide, exhibiting significant spatial and temporal heterogeneity across different regions and seasons. Although significant differences exist between the emissions of ocean vessels and inland vessels, their contributions to O₃ formation are becoming increasingly comparable. Solely controlling shipping emissions may not necessarily result in effective O₃ mitigation. Instead, coordinated reductions targeting both shipping and land-based anthropogenic sources, along with region-specific and targeted emission control strategies, are critical for achieving substantial improvements in O₃ pollution mitigation.