<p>Heatwaves (HWs) paired with higher ozone (O<sub>3</sub>) concentration at surface level pose a serious threat to human health. Their combined modulation of synoptic patterns and urbanization remains unclear. By using five years of summertime temperature and O<sub>3</sub> concentrations observation in Beijing, this study explored potential drivers of compound HWs and O<sub>3</sub> pollution events. Three unfavourable synoptic weather patterns were identified to dominate the compound HWs and O<sub>3</sub> pollution events. The weather patterns contributing to enhance those conditions are characterized by sinking air motion, low boundary layer height, and hot temperatures. Under the synergistic stress of HWs and O<sub>3</sub> pollution, the public mortality risk increased by approximately 12.59 % (95 % confidence interval: 4.66 %, 21.42 %). Relative to rural areas, urbanization caused higher risks for HWs, but lower risks for O<sub>3</sub> over urban areas. In general, unfavourable synoptic patterns and urbanization can enhance the compound risk of events in Beijing by 45.46 % and 8.08 %, respectively. Our findings provide robust evidence and implications for forecasting compound heatwaves and O<sub>3</sub> pollution event and its health risks in Beijing or in other urban areas all over the word having high concentrations of O<sub>3</sub> and high-density populations.</p>