Groundwater excessive exploitation has always been a main factor on the occurrence and development of land subsidence in Jiangsu coastal areas. The planning and construction of groundwater emergency water source has important practical and strategic significance for improving urban water supply security capacity and maintaining social harmony and stability. This paper took Binhai New Area in Nantong City as an example to realize rational exploitation and protection of groundwater resources and to effectively minimize the impact of the generated geological disasters. Two emergency water supply schemes were designed with the basis that groundwater resources should be used only as emergency water supply，and the geological risk prediction after the implementation of two emergency water supply schemes was carried out by establishing a coupling model of groundwater flow-land subsidence with GMS software. The results showed that under the condition of meeting the emergency water supply demand of Nantong Binhai New Area, the groundwater level falling funnel and ground subsidence only occur in the area where the emergency production well is located, after the implementation of the two schemes. In addition, after the emergency water supply ends, the underground water level rises rapidly, ground subsidence appears rebound phenomenon, the overall geological environment risk is very small, and both kinds of emergency water supply plans of groundwater are feasible.