Abstract: VOCs online monitoring was carried out in Qingdao City, Shandong Province from July 1 to 31, 2020, and the concentration, pollution characteristics, reactive activity and source of VOCs were analyzed. The results showed that the concentration of VOCs in summer of 2020 was (24.78±11.69)×10^-9, of which alkanes accounted for the largest content (44.79%), followed by aldehydes and ketones (21.98%) and halogenated hydrocarbons (16.85%). The results of atmospheric chemical reactivity of VOCs showed that alkenes contributed the most to ozone formation potential (OFP) and hydroxyl reaction rate (L_·OH), accounting for 37.10% and 55.63%, respectively. Butene, n-butane and propylene were the three species with the highest contribution to OFP and L_·OH. Positive matrix factorization (PMF) model was used to analyze the sources of VOCs, and five sources were identified, including liquefied petroleum gas (LPG) /secondary generation source (31.1%), fixed combustion source (22.6%), mobile source (20.6%), rubber and plastic production source (18.1%) and industrial solvent source (7.6%). The use of LPG was the key point of atmospheric VOCs control in Qingdao. The clustering results of backward airflow trajectories showed that Qingdao was mainly affected by the provincial urban air masses, the long-distance maritime air masses in the northeast, and maritime air masses in the east-southeast direction in summer. The short-range air masses from the province made the largest contribution to the local VOCs concentration in Qingdao.