For the legal status of U.S. patents, you need to check the website of the United States Patent and Trademark Office (http://www.uspto.gov/). The general steps are as follows: Through the USPTO website, enter the public query database (public pair) or enter directly through the URL: http://portal.uspto.gov/pair/PublicPair 2. Enter the verification code for verification: 3. Enter the patent To query: 4. Obtain the basic information of the patent you are querying: Here you can see the status of the patent you are querying. You can also query patent review process information through the "Image File Wrapper" tab, and query patent fee information through the "Fees" tab.