Abstract: We investigated ozone pollution and related meteorological factors in Liaoning province, China using hourly surface ozone concentrations and meteorological observations for the period 2015-2019. The ozone concentrations in Liaoning province appeared to be increasing significantly in all cities, except for several cities around Liaodong Bay. Ozone has taken over PM_2.5 as the main pollutant in Liaoning province. Ozone concentrations were high in summer, but low in winter; and high in the afternoon, but low in the morning. In addition to air pollution emissions, high temperature and humidity, intense radiation, low wind speed, and air pressure were the significant meteorological factors influencing the local ozone production. With the influence of the Asian Summer Monsoon, polluted air masses from upwind direction (e. g. North China Plain) under the southwestern wind influenced the air quality over Liaoning province.