The global epidemic has brought heavy disasters to people all over the world. The United States is the hardest hit area of this epidemic. According to the latest statistics, the cumulative number of confirmed cases in the United States has exceeded 1.38 million and more than 81000 people have died. What is most worrying is that the epidemic situation in the United States is still in the rising stage, but local governments in the United States have gradually begun to relax epidemic control, promote the resumption of production and work, and a large number of people have gathered, which will bring new hidden dangers to the spread of the epidemic.