Since the ancient time, the history of Sistan had a special position in national history of Iran- and even in the Islamic world. During the early years of the Islamic period, under the rule of the Saffarids, the history of Sistan appeared as the main center for the Iranian history due to its significance in the political events. After the fall of the Saffarids, A new group of the Sistani king, known as the Muluk of Nimruz, established their rule in Sistan and the adjacent area. By the rise of the Safavid rule, the Muluk of Sistan shared their power with the central government. After the collapse of the Safavids, these Muluk attempted to re-establish their authority there. The rule of Malik Mahmud of Sistan can be considered as the epoch of this activity. The information on the Maliks of Nimruz are scattered and there are nothing detailed information on the conditions of the Muluk in Zand and Qajarid sources. In recent years, according to new discovered manuscripts, titled as Shajarat al-Muluk, we can shed light on the history of Sistan during the period between the fall of the Safavids to the early years of the Qajara. The main task of this study is to examine the sources of this period and to focus on the importance of the Shjarat al- Muluk information on the history of the Kiyanid or the Maliks of Nimeuz.