Abstract: In July,a typical summer month in Lanzhou,the atmospheric volatile organic compounds were determined for 24 consecutive hours to study the pollution characteristics,ozone generation potential and source apportionment.The results showed that the average concentration of VOCs in Lanzhou super station was 99.59 μ g/m³.Alkanes accounted for 33.81% of the total VOCs concentration,which was the largest proportion of various organic substances.The ozone generation potential of VOCs was analyzed,and the top species were toluene,ethylene and vinyl acetate.According to sources apportionment for the VOCs by PMF model,the results showed that the sources of VOCs were mainly motor vehicles (31.30%),oil and gas volatilization/leakage (24.10%),solvent use (18.60%),combustion and chemical processes (17.20%),natural sources (8.80%).It was suggested that the control of motor vehicle emissions,oil and gas volatilization/leakage and solvent use should be the focus of reducing urban atmospheric VOCs emissions and ozone pollution prevention and control.