Abstract: The evaluation on development potential of urban underground space resource involves a lot of factors,and the appraising information is fuzzy and not complete. To resolve the problem,this paper makes a comprehensive evaluation on the development potential of urban underground space resource by fuzzy synthesis evaluation approach.Firstly,this paper develops the evaluation indicator system of development potential of urban underground space resource.Then,taking the five main sub-districts in Gulou district of Nanjing for examples,this paper applies fuzzy synthesis evaluation approach to the evaluation progress.The study shows that the fuzzy synthesis evaluation on the development potential of urban underground space resource is very effective to fill in the gaps such as fuzzy and incomplete evaluation information,and the evaluation result is reliable.