City renaissance has played an increasingly important role in urban regeneration since the mid-1980s. The concept of the Creative City, proposed by Charles Landry is driving the imagination of city redevelopers. Recent developments have focused less on capital projects and more on the ability of activity in the arts to support community-led renewals. It is essential for researchers to pay more attention to the issue of Creative City development. According to UNESCO, the Creative Cities Network connects cities that will share experiences, ideas, and best practices aiming at cultural, social and economic development. It is designed to promote the social, economical and cultural development of cities in both the developed and the developing world. However, Creative City design must be integrated with a wide range of knowledge and a diverse database. The application of urban development is a complex and delicate task. It involves multiple issues including engineering, economics, ecology, sociology, urban development, art, design and other domains. In order to empower efficiency in concurrent city development, appropriate evaluation and decision tools need to be provided. Building a decision support system of Creative City development can help decision-makers to solve semi-structured problems by analyzing data interactively. The decision support system is based on a new approach to treating rough sets. The method will play a pivotal role and will be employed dynamically in the DSS. The approach realizes an efficient sampling method in rough set analysis that distinguishes whether a subset can be classified in the focal set or not. The algorithm of the rough set model will be used to analyze obtained samples. In this paper we will first examine the design rules of Creative City development by urban design experts. Second, we will apply rough set theory to select the decision rules and measure the current status of Japanese cities. Finally, we will initiate a prototype decision support system for Creative City design based on the results obtained from the rough sets analysis.