The process of globalization makes economic exchanges among countries more and more popular all over the world. But along with this process, economic, political and social risks are also increasing. To protect economic security and avoid possible negative impacts from foreign direct investment (FDI) flows, some countries have taken measures to check foreign investment flows. The United States is a country with large FDI in the world and relies heavily on this capital to compensate for the shortage of domestic investment. However, due to concerns about national security from FDI inflows, US lawmakers have developed a mechanism to control FDI by introducing laws to assess, review, prevent and limit. FDI activities may threaten national security. Based on the analysis of the roles and activities of the US Foreign Investment Committee, the article addresses some comments about the US investment climate and prospects.