Abstract: This study investigates the airflow trajectory, transport path and potential source region of the ozone pollution event occurred in Hainan Province in October 2017 using AQI values and the concentrations of 6 atmospheric pollutants from meteorological observation data as well as the backward trajectory model (HYSPLIT). The results indicated that: (1) The days of main pollutant O₃ concentration in 13 cities exceeded more than 80% of the period, and the days in 9 cities reached 100%. On October 26^th, the AQI values in Chengmai County and Dangzhou City reached moderate pollution levels of 171 and 151, respectively. In addition, 7 cities reached a mild pollution level. (2) There was a good correlation between meteorological elements, AQI and pollutant concentration. The correlation coefficients between ρ(O₃) and AQI and relative humidity were -0.701 and -0.685, respectively, and passed the 99.9% significance test. (3) Satellite inversion indicated that exogenous transport had a direct impact on this pollution episode. The impacted airflows included long-distance airflows from inland, medium- and short-distance airflows from inland and short-distance airflows from the southeast coast. The corresponding AQI values of Haikou were 83, 69 and 61, and the corresponding ρ(O₃) were 135.0, 119.6 and 102.3 μg/m³ during the three airflow impact periods, respectively. (4) The potential source contribution factor (PSCF) and concentration weight trajectory (CWT) indicated that Guangdong Province was the main potential contribution region for this pollution episode. Besides, Hunan Province, Jiangxi Province, Jiangsu Province, Zhejiang Province and Fujian Province also had certain potential contributions. Overall, the pollutants that occurred in Hainan Province in October 2017 were mainly from exogenous O₃ pollution sources.