The COVID-19 pandemic has brought an unexpected and disastrous impact on the U.S. economy，society and science and technology sector. It highlights the importance of strengthening public health innovation and cooperation，and building up a corresponding strategic reserve of science and technology. It also further exposes the fatal problem of the Trump administration’s neglect of public health security and disregard for science. Meanwhile，in the context of great power competition，the Trump administration has kept on advancing key R&D areas from the perspectives of national security and future industries，taking measures to suppress China and seeking to maintain its technological superiority. However，it has failed to translate the vision of launching the “second bold era” of American scientific and technological development into a concrete roadmap，and caused a major turning point in US science and technology policy，which has greatly deviated from its tradition of openness and cooperation，and has particularly caused the damage to science in several ways. But bipartisan support in the Congress ensured that federal R&D investment has increased and major programs have moved forward. With the victory of Democratic candidate Joe Biden in the presidential election，U.S. science and technology policy will once again witness some major reversals.