Ozone pollution is a significant environmental problem for some cities in China at present. The ozone formation depends on the chemical reactions affected by the atmospheric physical process and various meteorological conditions, so it is necessary to study near-ground ozone pollution from both chemical and physical aspects. This study analyzed the physicochemical processes of photochemical pollution in Huairou, an urban city in Beijing, in autumn 2022, by combining field observations and the Eulerian photochemical box model simulations. The daily variation characteristics of meteorological factors, such as temperature, relative humidity, and wind speed, and the concentrations of ozone and its precursors, volatile organic compounds (VOCs) and nitrogen oxides (NOx, x=1, 2), are determined. The results of source analysis show that the primary sources of VOCs were traffic emissions (46%), plant sources (25%), solvent evaporation (23%) and combustion process (9%). The contribution of ozone from regional transport and reactions of local VOCs was obtained based on the Euler photochemical box model. The results show that ozone was mainly from horizontal transport (> 74%) during the strong north wind prevailing period. During weak south or southeast winds, O3 was formed primarily by VOCs and NOx photochemical reactions. According to the ozone formation potential of VOCs, alkenes contribute the most to ozone formation, accounting for 67%, followed by aromatics (16%). Sensitivity analysis shows that ozone formation is most sensitive to physical factors, such as light intensity, temperature and boundary layer height; meanwhile, reactive alkenes are the most sensitive among VOCs. Finally, O3 pollution control strategies are suggested based on the EKMA curves.