Abstract: The construction of city information model (CIM) needs to settle transformation of various data in a unified coordinate system. By sorting out the commonly used coordinate systems, this paper analyzes the conversion principles between different coordinate systems, introduces the application cases of the BIM model conversion process under the CGCS2000 projected coordinate system and the Nanjing local projected coordinate system, and finally proposes a set of integration solution from BIM model to CIM platform under heterogeneous coordinate systems.