Continuous measurements of 116 volatile organic compounds (VOCs) species by online gas chromato-graphy-mass spectrometry (GC-MS) from autumn 2023 to summer 2024 in Urumqi and Karamay were used to investigates the pollution characteristics of VOCs, the potential contribution to secondary pollutants, and their sources. The results showed that the average VOC concentration in Urumqi ((31.08±20.7)×10⁻⁹) was higher than in Karamay ((23.08±20.9)×10⁻⁹). Both cities showed a seasonal variation trend with lower VOCs concentrations in spring and summer and higher concentrations in autumn and winter. In Urumqi, alkanes (38.7%) and oxygenated volatile organic compounds OVOCs (16.7%) were the primary components of VOCs, whereas in Karamay, the proportion of alkanes reached as high as 47.2%, followed by alkenes (13.7%). The ozone formation potential of VOCs in Urumqi and Karamay in summer was 139.2 μg/m³ and 46.7 μg/m³, respectively, mainly contributed by OVOCs (38.2% and 41.8%). In winter, secondary organic aerosol formation potential were 0.59 μg/m³ and 0.41 μg/m³, respectively, mainly contributed by aromatics (89.8% and 84.8%). OH reactivity in Urumqi (5.0 s⁻¹) was higher than that in Karamay (2.6 s⁻¹). Alkenes were found to be the major contributor to OH reactivity. Positive matrix factorization (PMF) source analysis for the two cities revealed great similarity, with the common factors including combustion, traffic exhaust, solvent evaporation, industrial emissions, and regional background. Combustion and traffic exhaust contributed the most to ambient VOCs concentrations in Urumqi and Karamay at 23.8% and 23.5%, respectively, which was high compared with other cities in China.