Inquiring into the northern region of Tianshan Mountain valley oasis, urban traffic and the link between tropospheric NO₂ vertical column density, Employing ground-based multi-axis difference spectrometer, (Mini MAX-DOAS) in 2018—2019, the north slope of Tianshan Mountains, economic belt comprehensive city Urumqi, Shihezi and in addition, medium-sized city, small continuous fixed monitoring Fukang city downtown area, carrying on the vehicle-mounted mobile monitoring on the city traffic trunk road, based on the urban traffic condition. Studying the influence of the tropospheric NO₂ vertical column density, and analysis of mountain valley oasis city with developed cities of middle basin system’s pollution differences. The results show that: (1) Medium cities of the north slope of Tianshan Mountain cities of daily mean value flow in Urumqi (1 406/5 min) greater than the small and medium-sized cities, medium-sized city Shihezi (203/5 min) and the small city Fukang (185/5 min), there is no significant difference (p>0.05), and all kinds of city NO₂VCD overall significant difference (p<0.05), the daily variation of the peak, Urumqi (22.613×10¹⁵ molec·cm^-2)>Fukang (17.758×10¹⁵ molec·cm^-2)>Shihezi (15.272×10¹⁵ molec·cm^-2). The daily variation trend of traffic flow and NO₂VCD in the three cities is consistent, showing a trend of “high in the morning and evening, low at noon”. In the seasonal variation, the traffic flow and NO₂VCD of the three types of cities are: winter and spring>autumn and summer; (2) Although the traffic flow at the monitoring points in the morning and evening is different, the traffic flow of the three types of cities is concentrated near the city center; The movement monitoring data show that the high NO₂VCD value occurs in urban areas with high traffic flow, and when the wind direction is stable in each city, the downwind concentration is greater than the upwind concentration. Due to the differences of living space, people’s activities in various functional areas of the city, traffic flow and NO₂VCD are concentrated in the commercial district with dense population, indicating that vehicles have a great contribution to NO₂VCD; (3)2009—2019, ten years north slope of Tianshan Mountain medium cities economic growth rate of GDP over 200%, Urumqi, Shihezi motor vehicle growth rate than developed cities such as Beijing, Shanghai, rapid urban development, and in the valley oasis area, low meteorological terrain north, the winter inversion layer, deep calm wind days more, heating period 6 months long, causing serious pollution in winter. In addition to the anthropogenic pollution discharge, natural factors contribute to the accumulation of pollutants in the north slope of Tianshan Mountain.