Abstract
The purpose of this study is to reveal the evolution process of spatial formation between the Piazza del Popolo in Rome and its circumstances. In order to facilitate the research, 4 situations of different periods and urban contexts around the Piazza del Popolo were reconstructed and compared, in base of various documentations including iconography, cartography, bibliography and photography. In conclusion, the spatial transformation of the Piazza del Popolo is the result of complex elements and situations but the relationship between the obelisk of the piazza with trident streets and the coordination between the inner space of the piazza and the Pincio Hill are the most decisive two factors for defining character and image of the piazza today. The piazza itself was not completed at once but formulated over centuries and in urban scale, it has the meaning of important node point related to the trivium streets and the Via Flaminia, at the same time to the Vatican area across the river Tevere through the Margherita bridge and Via Cola di Rienzo.