As the globalization is developing, financial interdependence has been increasing sharply among financial organizations, such as central banks, commercial banks, investment banks, etc.. And the relationships in this system can be perfectly explained as network structure. Many researchers have studied a lot in this intersection. In this paper, we select 158 literatures (2004-2016) from SSCI journals, and summarize the relative researches about network theory applied to the financial system in the western world. This research shows the development of financial network theory and four aspects of latest research results. In the future, IT will be the major driving force and the most popular solving method to analyze the financial network related problems.