Tomb sites, due to the prominent construction features, execution methods and decorative elements, account for an important part of the Iranian architectural patterns in the Islamic period in the group of burial buildings. Regarding to the fundamental importance of these sites, from a scientific point of view, research in various dimensions of their formation and emergence and comprehensive study is of great importance. One of the most important structural issues of tomb sites is determining the exact date of construction and developments that have affected their structures over time. The complex of Sheikh Ahmad-e Jam, in the city of Torbat-e Jam, which was founded by the will or to advance the governmental and political goals of one of the Khorasan mystics in the fifth and sixth centuries AH, is among the magnificent works of Iranian architecture and one of the most valuable historical sites in Iran. This complex have reflected a full image of Iranian-Islamic art and over time, has been one of the major centers of mysticism and Sufism in eastern Iran and the land of Khorasan. Despite this position and importance, many architectural features and decorative arts in this complex are still unknown and neglected.Among the buildings in the complex of Sheikh Ahmad Jam’s tomb, the dome chamber or solitary room (a place for worship), besides having a mystical and spiritual virtue for his children and grandchildren, one of the most important features of this building is the existence of a unique credential-narrative inscription of Al-Kart kings of Herat and a figure named "Gheymus" in it, and on the other hand, the focus of decorative patterns in the form of murals, inscriptions and paintings in various designs, has doubled the importance of the dome chamber of Jam’s tomb. Therefore, the purpose of this study was to investigate and explain the architectural components and elements of this building by examining the concept and semantics of their array patterns. This research was conducted with the ultimate goal of obtaining answers to following questions. (1) Is the building of the dome chamber the same plain monastery of Sheikh Ahmad Jam, which was renovated by Sultan Sanjar after his death? (2) What justifies the existence of inscriptions and decorative elements in the interior space and their special concept and meaning? (3) Were the inscriptions and images written and drawn at the same period of time? However, in order to scientifically answer these questions, the research method and data collection of this study are based on documents and records, field studies and of laboratory tests and its approach is descriptive, comparative and interpretive analysis.