Sistan plain, in the southeast of Iran, had an important role in connection ofconnecting societies in the past, and with good biological conditions and fertility, it has been recognized as one of the most important human societies in various historical periods. Despite numerous archaeological activities in this area, the chronology of this area is ambiguous, so Itand as such it is necessary to conduct a systematic study onof the historical sites of the Sistan plain. The research method was analytical and field research. For this purpose, some sounding haswas been dug for determining the extent of the Bibi Dost site, and a survey of Ghalee Tepe, in the southern part of the Bibi Dost area, has been done. In this paper, all information and data related to the site, like previous studies in that area, plus geographical literature and pottery references, has been accumulated. Based on pottery comparison, this site has been inhabited in the Parthian and Sassanid eraeras, and after a long gap the southern part of this citadel has been used as a cemetery in the later Islamic ages.