Abstract: Based on the analysis of the special hydrogeological conditions of an ancient river in Wuhan, a hydrogeological model for the ancient river is established. The problem of artesian well flow in the ancient river is generalized to that of groundwater movement to pumping wells in belt-like artesian aquifers. Then, based on the principle of mirror method and the potential function, the formulas of steady flow for artesian and artesian-unartesian completely penetrating wells in the ancient river are derived. On this basis, it is applied to the foundation pit dewatering project, and a method for calculating the water inflow of the foundation pit of artesian aquifers in the ancient river is put forward. Finally, taking the deep foundation pit of the underground parking lot of Liyuan Plaza in Wuhan as an example, the calculated results are compared with those of the traditional methods and the actual monitoring data. The results show that the relative error between the calculated results and the actual water inflow of the foundation pit is only 7.4%, while the relative error of the traditional method is 54.5%, which verifies the rationality of the proposed method. The research results are of great significance for understanding the theory of artesian well flow in ancient rivers and for guiding the design of foundation pit dewatering projects.