3D mapping is a difficult problem due to real-world places whose appearance and scale can be various. Owing to the rapid development of computer and robot system, remarkable improvements of performance are achieved in 3D map technology, which in turn contribute to the significant advances in SLAM. This paper presents the state-of-the-art 3D map technology and system, which is classified into topological maps, metric maps and semantic maps. Additionally, the advantages and disadvantages of various 3D map technologies are analyzed in different aspects, including navigation performance, localization performance, visual perception, scalability, computation cost and mapping difficulty. In order to better understand them, the key performance parameters of the 3D map technologies are compared in a table. Finally, the paper ends with a discussion on the open problems and future of 3D map technology.