This study is to analyze the spatial characteristics of the city of Sabbioneta as an Ideal City of Renaissance. Architectural treatises in Renaissance reflected rational, logical and practical view of the human being as well as aristocratic and dominating nature of governing class. These theories and the new fortification system were applied on the planning of Sabbioneta. It can be recognized by the hexagonal appearance of the city, bastionated city wall, and the segmented street pattern which is based on the gridion system. Magnificent two piazzas and their location, shape, size and arrangements are also the proofs of authority and dignity of the Prince. Wide and straight streets which is distinctive from medieval ones, L and T shaped street system and the observation system through carefully planned two city gates gets advantages not only in a line of defense but also in the rich visionary experience. Thanks to the great concern of the prince who wanted to make his city meet the ideal state of classical Roman Greek ideal, Sabbioneta has various humanistic and aesthetical programs. In these respects, Sabbioneta made a significant development of ideal city and provided future directions for further ideal cities and urban planning.