Abstract: Urban underground space is an important spatial resource for future cities and an indispensable part of sustainable development strategy.In order to support the scientific development of underground space in Nanchang, the geological environment influencing factors were identified from five aspects, including topography and geomophology, engineering geological conditions, hydrogeological conditions, active faults and seismic effects, and environmental geological issues.Based on the construction of an evaluation index system for the geological suitability of underground space development, the geological suitability of underground spaces at different depths was evaluated through analytic hierarchy process and grey relational analysis.The results show that the geological conditions of the middle underground space in the study area are complex, and the shallow and deep layers are more suitable for development.This result provides technical support for the preparation of the special plan for underground space in Nanchang.