As the global climate change problem is becoming more and more serious, China has made the commitment to the "dual-carbon" target. At present, our country has not fundamentally solved the issue of PM_2.5 pollution. Meanwhile, O_3 pollution is gradually worsening, and incidents of combined PM_2.5 and O_3 occur frequently. Therefore, the sustained improvement of PM_2.5 and O_3 pollution is of great significance to protect people's health and achieve carbon neutrality goals. To better understand and address PM2.5 pollution, this paper provides an overview of the effects of NO_x and NH_3 emissions, as well as secondary organic aerosols on PM_2.5 pollution. Additionally, it summarizes current researchon the influence of emission sources (nitrogen oxides, volatile organic compounds) and meteorological factors (temperature, relative humidity, UV radiation intensity, wind speed, boundary layer height, etc.) on O_3 pollution in China, which provides methodological and theoretical support for improving O_3 pollution and developing reduction strategies in our country. Furthermore, this paper summarizes the research progress on the regional delineation, chemical mechanism and influencing factors of PM_2.5 and O_3 combined pollution in China, aiming to provide relevant references and guidance for China's follow-up action plan to improve air quality, protect the environment, and realize the synergistic management of PM_2.5 and O_3 combined pollution under the "dual-carbon" policy.