Abstract：Karst geological survey and evaluation methods for urban geological survey remain in the exploring stage in China, and there exist no available technical codes and guidelines. On the basis of Hangzhou urban karst geological characteristics and the demands of Hangzhou economic society for karst geological survey, the authors tried to find urban karst geological characteristics and evaluate the stability of the key karst subsidence blocks. Data from previous work were fully used, supplementary investigation and dissection of key points were made, and the combination of geology, geophysical exploration, drilling and fuzzy layers analysis were implemented. These measures have greatly promoted the research level of karst geological characteristics and the forecast of karst subsidence in this area. The working methods are also actively studied in this paper.