Abstract: The detailed distribution of traffic flow with high temporal-spatial resolution is an important basis for research on motor vehicle emissions. This study obtained information on the vehicle volume and vehicle technical characteristics information in the second ring district of Chongqing City every 10 minutes according to the Radio Frequency Identification Device and vehicle registration data. In addition, the temporal-spatial distribution characteristics of vehicle volumes were compared and analyzed through various vehicle types, road types, emission standards and fuel types between the inner and outer districts. The main conclusions are as follows: The average daily traffic volume in the inner district was 1.8×10⁴ vehicles per day, which was about 1.8 times that of the outer district. Specifically, the proportions of light passenger cars, buses and taxis in the inner district were 1.7, 2.1 and 2.5 times larger than that of the outer district, respectively, while the proportion of heavy trucks was 54.8% of the outer district. The main fuel types in the inner and outer districts were gasoline (71.7%-73.7%), natural gas (15.1%-21.4%), diesel (5.5%-9.6%) and new energy (1.3%-1.5%). The distribution of emission standards in the inner district was the same as that of the outer district, with China Ⅳ accounting for about 76.5%, China Ⅴ accounting for about 11.4%, China Ⅲ accounting for about 9.0%, the sum of the proportions of China Ⅱ, China Ⅰ and under China Ⅰ is about 3.1%. The hourly total volumes change characteristics of the two districts both presented an 'M' shape, and the peak hours occurred during 08:00-10:00 and 16:00-18:00, respectively. In addition, the hourly volume change characteristics of light passenger cars and buses in the two districts were consistent with the total volume flow characteristics, while taxis, light trucks and heavy trucks showed continuous upward trend from 08:00 to 14:00. Finally, the peak period volumes of different types of roads in the two districts were quite different. The peak period volumes of highways, expressways and county roads in inner district were about 5.5, 2.5 and 6.2 times larger than the outside district, respectively. On the contrary, the peak period volumes of national highways in the outer district was 1.8 times larger than that of the inner district. The results indicated that the vehicle flow and vehicle characteristics information are significantly different between the inner and outer districts. More attention should be paid to the refined temporal-spatial monitoring network of urban traffic flow to provide better data support for the compilation of vehicle emission inventories.