In the first year of Trump administration，the immigration policy of the United States has a major turn，which not only has a significant impact on the domestic society but also brings great changes to international setup. On the basis of the statistical yearbook of the Department of Homeland Security and the visa information issued by the US foreign ministry since 2008，this paper analyzes U.S immigration of 2017 from multiple perspectives. Compared with relevant policies and immigration data in Obama’s tenure，the number of legal immigrants in various categories has been significantly reduced and many indicators have reversed the trend of growth in the past decade. This is a reflection of the prevailing anxiety among the middle class of U.S and a direct consequence of the increasingly tense international security situation. Finally，this paper analyzes the influence of Trump’s immigration policy on all kinds of immigrants，social and economical development of U.S and global diplomacy. We draw the conclusion that in the short run，the tightened immigration policy can fight against illegal immigration，reduce the crime rate and relieve the unemployment problem of some low-skilled American blue collar workers. However，in an irreversible context of globalization，this will also reduce the attractiveness to high-end immigrants，increase the financial burden and the complexity of the border conflicts. As the most important nation of immigrants is growing conservative，a new trend in the international immigration system can be expected.