This article describes the foundation pit dewatering case of the underground support project of the Comprehensive Passenger Transportation Hub in the East of Yangzhou, where step-slope excavation is adopted as well as diaphragm wall and inner support in the foundation pit excavation. Since the aquifer is thick and highly permeable, deployment of the dewatering wells, either at the bottom of the slope or the inter-slope platform, will directly affect the dynamic control of dewatering. In this paper, two dewatering plans are proposed for comparison: in Plan 1, wells are arranged at the slope bottom; while in Plan 2 wells are arranged at the inter-slope platform. Comparison results from the numerical simulation method show that: in Plan 1, although the number of wells and the final total flow rate are slightly smaller than the those in Plan 2, the need to pre-dewatering will result in a large amount of water waste; in Plan 2, the pumping well number can be gradually increased with the depth of the excavation, reflecting the principle of dewatering on demand. Therefore, Plan 2 is considered to be better. This research can serve as a reference to the dewatering design of similar foundation pits: not only shouldthe total number of wells and the final total flow rate be considered, but also the different excavation stages. By implementing the principles of dynamic control and dewatering on demand, the green construction of foundation pit works can be realized from the very start.