Urban agglomeration is a regional complex ecosystem developed by the integration of substance, energy and labor flow between cities after urban development to a high level. How to ensure the ecological security and sustainable development of urban agglomeration has become a hot topic. Through literature review, this paper analyzes the characteristics of ecological security, urban ecological security and urban agglomeration ecological security. In a broad sense, the ecological security of urban agglomeration needs to consider not only the optimization of ecosystem pattern and function as well as the balance of supply and demand of ecosystem service, but also the tele-coupling relationship between urban agglomeration and the other regions. The goal of building eco-security pattern in urban agglomeration is to ensure the coordinated development of regional integration within the urban agglomeration, to meet the basic needs of human daily life, and to realize the regular circulation of substance flow, energy flow and labor flow between urban agglomeration and the other regions. When an eco-security pattern of urban agglomeration is to be established, the following principles have to be followed: (1) the difference of supply and human demand on ecosystem services in different levels; (2) the threshold effect of eco-security for different cities; (3) the spatial synergistic linkage of eco-security pattern. Finally, the basic idea and technical roadmap to build eco-security pattern in urban agglomeration was proposed.