Ozone (O3) and fine particulate matter (PM2.5) are the major air pollutants, and CO2 is a critical greenhouse gas in East Asia. They three are active species in terms of radiation. Most importantly, both O3 and PM2.5 can interact with CO2 through the terrestrial ecosystem, thus having effects on the regional climate. This study investigated the mutual interactions among O3, PM2.5, and CO2 on the East Asia summer monsoon climate using the coupling regional climate-chemistry-ecology model, RegCM-Chem-YIBs. Two numerical experiments were performed with and without involving the interactions among the three species. The investigations showed that the mutual interactions finally resulted in changes to surface PM2.5, O3, and CO2 of -6∼-2 μg/m3, 4∼6 μg/m3, and 3∼5 ppm, respectively, in northern China. While in southern China, surface PM2.5, O3, and CO2 varied in the range of 2∼4 μg/m3, 1∼2 μg/m3, and -4∼-2 ppm. Surface downward shortwave radiation flux (SWF) and longwave radiation flux (LWF) increased in northern China, whereas showed decreasing in southern China. The lower atmosphere was warmed by 1∼2 K in north China, enlarging the air temperature gradient between land and sea, inducing easterly and southerly winds at 850 hpa in the region. On the contrary, surface cooling (-2∼-1K) exhibited northerly wind anomalies in southern China. The results indicated that the mutual interactions among the three species could significantly impact regional climate. We argue that future simulations should consider these interactions to better predict air pollution and climate changes in the target region. This work could help to comprehensively understand the climate effects of the mutual interactions among O3, PM2.5, and CO2. The findings provide a scientific reference for the collaborative governance of regional climate and air pollution in East Asia.