The spatial pattern of trip distrbution in a metropolitan area can be used at a device to describe the spatial organization of the metropolitan area. In this study, Taichung Metropolitan Area is selected as the studying area and entropy is used as an aggregate indicator of the spatial pattern of trip distribution. Based upon the results, it shows that Taichung Metropolitan Area lacks strong central tendency and association among its sub-districts. In addition, it also indicates that the real Metropolitan Area should be smaller than what currently consists of.