ʿĀli Qāpu Palace among the magnificent buildings constructed during the Safavid period (907-1135 AH) in Isfahan, is considered one of the most famous ones. Although the Palace has been of interest to experts in various fields such as restoration, architecture, and the history of art, its archaeological studies have been neglected. The lack of study of the water supply system of the palace since the time of its construction, has been one of the notable aspects causing many unrealistic assumptions. The authors of this article attempt to investigate its components, and functioning, using written, oral, and documentary sources on the remains of the water supply structure of ʿĀli Qāpu Palace. The documentation of the remaining evidence and the study of primary sources alongside the data obtained from the restorations have shown the high level of knowledge and understanding of the mechanics of the creators in establishing an efficient and coordinated system for the water supply and transfer to the upper floors of the Palace. This kind of water supply and water cycle was derived from machines built in the centuries before the reign of the Safavid, which by its application had facilitated water transfer in the Palace. Thus, this study not only leads to the identification of the water supply facilities of ʿĀli Qāpu Palace and the cycle and transfer of water in different parts of the building but also provides the basis for the recognition of the subject in similar structures.