Mehr worship is one of the ancient Iranian rituals, whose history, based on the available documents and information, dates to at least the 4th millennium BC. M. Researchers believe that groups of Aryan tribes introduced this ritual was to Iran and then spread it.  However, there are signs of its very ancient and indigenous history. The influence of Mehrism or in other word, Mehrism was such that some beliefs and customs of Mehrism gradually entered Zoroastrianism with the advent of Zoroastrianism; As in several inscriptions from the Achaemenid era, "Ahuramazda, Mehr and Nahid" have been sworn. Due to the spread of this ritual in different parts of the Iranian plateau and even in Europe, many of its manifestations are still available and can be studied. Therefore, the main question of this article is that how many types of architecture the spatial structure of Mehri (Mithraism) shrines has? The purpose of this research is to investigate and document 14 Mehri shrines in the geographical boundaries of ancient Iran. The current research is based on the historical research method, based on library and field (archaeological) study. The results of the research show that Mehri shrines were built with rocky and underground spatial structure, next to rivers, springs, with cradle arches and, were decorated with star motifs, small openings in the roof and with simple decorations.