The Sagittarius or Rami Constellation comes in the form of a Centaurus drawing a bow and pointing arrow at its dragon tail. This role has repeatedly combined various factors of astrology, astronomy and mythology; and created the combination of scientific enthusiasm and aesthetic taste of the artists. These works can be classified into two categories: the first are drawings that are extracted from astronomical treatises and represent it through the science of astronomy; the second are created from an aesthetic point of view and based on the astrological rules influenced by the worldview of their era. This research conducts a visual study on Sagittarius constellation with an iconological approach in three stages of “description”, “analysis” and “interpretation”. Likewise, adopting a descriptive-analytical approach of this icon, attempts are made to answer the question of “in what ways does the role of Sagittarius exist in the architectural monuments of Isfahan and other astrological works of Iran during the Islamic period, with an emphasis on the spandrel of Qeisariah gate in Isfahan.” The study revealed that the Sagittarius constellation on the spandrels of the monuments in Isfahan is a reflection of its astrological ancient kind in the Babylonian boundary stone and other astrological kinds of the Islamic period. Yet, various shapes of the Sagittarius constellation in connection with the myths are considered as artistic attempts to break away from similarities in its scientific origin. Sagittarius comes in the form of half-horse in the astronomical scientific texts based on astrology, and mainly on the basis of astrology rules and connecting with the myths in combination with dragon in the artificial and architectural arts. The drawing methods are also in different forms by adding various colors and decorations from linear designs in astrological versions to painting methods in the tile works of architectural monuments such as Qeisariah.