Regional ozone pollution has become one of the most challenging environmental problems in China. In July 2019, hourly real-time monitoring of ozone (O₃) and nitrogen oxides (NO_x) and 3-h off-line measurement of volatile organic compounds (VOCs) during a 10-day intensive campaign were conducted at four sites in Taiyuan, Shanxi Province, China. The average mixing ratio of total VOCs (including alkanes, alkenes, aromatics and acetylene) was 14.8 ± 2.8 ppbv and the dominant VOCs species to O₃ formation were alkenes in Taiyuan. According to China Ambient Air Quality Standard Grade II (hourly averaged mixing ratio of 103 ppbv), the studied periods were divided into O₃ attainment periods (EP1) and O₃ pollution periods (EP2). A continuous O₃ pollution event was captured during 12–15 July, with the maximum hourly O₃ mixing ratio of 131.7 ppbv. Higher temperature, lower relative humidity, weaker winds and local photochemical reaction were conducive to O₃ pollution during EP2. The analysis of VOCs/NO_x ratio indicated that the formation of O₃ was co-controlled by both VOCs and NO_x during the period of 12:00–18:00 LT (high value period of O₃), and it was controlled by VOCs during the remaining period. The abundances, compositions of typical VOCs and VOCs/NO_x ratio showed clear spatial and temporal variations. Six major sources of VOCs were identified by positive matrix factorization, including coal and biomass combustion (33%), coking sources (28%), vehicular emissions (14%), solvent usage (10%), industrial processes (8%) and biological sources (7%). Backward trajectory analysis found that higher concentration of O₃ in air masses from local (70%) and southern areas (22.5%) during EP2. Local (32%) and southern (30%) coking sources were the main contributors of ozone formation potential (OFP) during EP2.