Abstract: The pre-exploration is the basic premise of scientific exploitation and utilization of underground space resources. Although significant investigation and evaluation have been carried out in many large cities in China, there is no published systematic summarization of exploration. On the basis of investigation and evaluation of urban underground space in Beijing, this paper describes both detection objects and methods for underground space resources in built-up areas and places to be built respectively, which represent two key steps of underground space utilization. In built-up areas in Beijing, underground space is calculated by affected depth of buildings in the vertical direction with the application of various geophysical prospecting methods, including electrical method, magnetic method, gravity detection and seismic techniques, which can define exploited underground space accurately. On the other hand, geological conditions which are likely to have impact on underground space development become the major research objects in areas to be built. In addition, a practical example is summarized to explain the concrete operation, with the expectation of providing references for related work of urban underground space resources.