Serlio dealts with mainly architectural order in his Fourth Book of Architecture and he exlpains many design of church, palazzo, porta and so on in it. There are ionic palazzo fagades and corinthian ones in seventh and eighth chapter, and two of them represent whole form of palazzo. This paper analyses these two palazzo design by applying the method of constructing a porta. The results of the analysis in this paper are as follows ; The method of constructing a porta is used in the square that relates to whole form of palazzo to decide geometrically the diameteter of column. The whole form of palazzo is derived from an applied fundamental square, and this square is also used for designing its facade composition by applying the method of constructing a porta. The facade composition is previously decided by square, and some parts of it are decided by architetural order.
