It has been long believed there should be some relations between traffic system and urbanization,but the in-teraction between them,especially on the regional level,has been not in consideration due to the difficulty in quantitative analysis.Based on the development of Jilin Province during 1981-2003,the paper analyzed the relation with the grey-relation model which was adjusted to fit specific problem,and came to some conclusions.Firstly,there exists ob-vious and strong correlation between traffic system and urbanization.Secondly,urbanization responds to the develop-ment of traffic system mainly on the level of urbanization,such as population and developed area,however,less on urbanization quality.Thirdly,traffic system influences urbanization as a whole except for several peculiar factors,which means we should optimize the whole traffic system to promote urbanization.Based on those conclusions,the paper illustrated the mechanism of traffic system,promoting urbanization scale and urbanization quality. It has been long believed there should be some relations between traffic system and urbanization, but the in-teraction between them, especially on the regional level, has been not in consideration in to the difficulty in quantitative analysis.Based on the development of Jilin Province during 1981-2003, the paper analyzed the relation with the gray-relation model which was adjusted to fit specific problem, and came to some conclusions. Firstly, there exists ob-vious and strong correlation between traffic system and urbanization. Secondarily, urbanization responds to the develop-ment of traffic system mainly on the level of urbanization, such as population and developed area, however, less on urbanization quality.Thirdly, traffic system attempts urbanization as a whole except for several peculiar factors, which means we should optimize the whole traffic system to promote urbanization. Based on those conclusions, the paper illustrated the mechanism of traffic system, promoting urbanization scale and urban ization quality.