Abstract: City Information Modeling(CIM)is a digital description and expression of the thematic, spatial and temporal characteristics for various city physical objects above ground, underground, indoor and outdoor. It has received widespread attention now, and several cities or districts are carrying out CIM construction pilot projects. However, there is still a lack of systematic and in-depth research on the issues of what CIM is, what characteristics and basic components it has, and how to construct it. Based on the analysis of the concept, essential characteristics and components of CIM, this paper focuses on the main questions of CIM data construction and put forward suggestions to build CIM basic data on the use of the fundamental data in the information system for digitized supervision and management of city, the geo-entity data in the new fundamental surveying and mapping, the results of the joint surveying and mapping for engineering construction project approval, and the housing and infrastructure risk survey information.