The purpose of this study is to analyze the relationship between urban spatial characteristics and commuting behaviors. Throughout the reviews of various theoretical and empirical studies on urban form and structure and its effectiveness, a hypothesis will be introduced and tested by an empirical analysis of South Korea cities. The analysis of selected South Korea cities is based on data drawn from the 2000 and 2005 Population and Housing Census. Basically, the paper analyze the modal choice and commuting times in four ways: by comparing the urban density, the urban size, job/housing ratio, and population aging rate. The analysis shows the negative(-) relationship between the four urban spatial characteristics and commuting mode choice accepting compact city hypothesis. However, the relationship between commuting time and the density, size, and job/housing ratio shows positive(+) rejecting compact city hypothesis. This outcome is resulted from the inefficiencies of urban transit required massive investments in metropolitan area. This result indicates the weakness of new urbanism in Korea cities.