Abstract: To explore the causes of O₃ pollution and the pollution characteristics and sources of VOCs of Nanyang, a typical city in central China, a one-year online observation of atmospheric O₃ and its precursors (VOCs, NO_x and CO etc.) was conduct in 2022. It is found that the monthly average concentration of O₃ in Nanyang is higher from May to September (which is defined as ozone pollution frequent months), and the highest monthly average concentration occurred in June (154 μg/m³). In the ozone pollution frequent months, when the hourly average temperature is higher than 25℃ and the relative humidity is lower than 60%, ozone pollution is easy to occur. Empirical kinetic model (EKMA) and relative incremental reactivity (RIR) calculation showed that in ozone pollution frequent months the O₃ formation sensitivity was in transitional region, which implied that the O₃ formation in Nanyang was sensitive to both anthropogenic VOCs and NO_x. The average concentration of TVOCs in Nanyang during the observation period was (26.3±15.0) ×10^-9, and the top three abundant species were formaldehyde (5.3±4.7) ×10^-9, ethane (3.4±2.2) ×10^-9, and acetone (2.1±0.9) ×10^-9. The concentration of formaldehyde in Nanyang was significantly higher than that in other cities. And the primary emission is found to be an important source for formaldehyde of Nanyang. The ozone formation potential (OFP) of formaldehyde, acetaldehyde and ethylene, m-p-xylene and toluene in ambient air was significantly higher than that of other species. In addition, the results of the positive matrix factorization model (PMF) of the ozone pollution frequent months showed that gasoline vehicles (29%), solvent use (23%), industrial process emissions (21%), residential emissions (11%), diesel vehicle emissions (10%) and plant emission (6%) are the main sources for atmospheric VOCs of Nanyang. This is the first study on the causes of O₃ pollution and the characteristics and sources of VOCs pollution in Nanyang, aiming to provide a guidance for O₃ pollution control in central China.