In this study, Urban Heat Island(UHI) effects of Seoul were spatially analyzed with building characteristics of urban areas. Ground Coverage Ratio(GCR) was adopted to represent urban building characteristics of Seoul. GCR stands for coverage ratio of building in a unit grid which is 30m in this study. Afterward, Land Surface Temperature(LST) derived from satellite remote sensing image was used as an indicator for UHI of Seoul. Furthermore, for more precise analysis, residential areas near cool islands such as mountains, large green spaces, river were removed from analysis area in order to analyze independent effect of structural characteristics with LST. To build up GCR, 2015 Seoul building data provided by Ministry of Land, Infrastructure, and Transport was used. For thermal index, time series Landsat8 images of 2014-2016 summer were used to derive 3 year average LST of Seoul. Statistical analysis between two indices showed strong linear relationship between LST and GCR.