Abstract: The emergency water source, as an unconventional temporary water source to solve the urban water source crisis when the water supply is difficult due to emergencies, is an important guarantee for urban water safety and social stable development.Taking the representative Dasong River Basin in Ningbo City as an example, and from the perspective of rational utilization and effective increase of underground freshwater resources, we proposed a regional emergency groundwater supply mode that combined “valleys” freshwater sources, “sealed” freshwater sources, and underground freshwater reservoirs.Then, the construction conditions of phreatic water emergency water source of Tangxi valley, 2nd confined aquifer's sealed freshwater emergency water source of Xianxiang plain, and 1st confined aquifer freshwater reservoir of Xianxiang plain were analyzed.The results indicate that phreatic water of Tangxi valley and the 2nd confined aquifer's sealed freshwater of Xianxiang plain have great potential of emergency exploitation as emergency water source.The 1st confined aquifer of Xianxiang Plain has good conditions of underground freshwater reservoir construction, and can effectively increase underground freshwater resources by regulation of regional water resources.The emergency water supply mode that combines multiple types of groundwater sources can sufficiently excavate and reasonably use the potential of regional underground freshwater resources, and provide references for the emergency water supply security system of Ningbo City.