U.S. trademark registration inquiries are mainly conducted through the website of the U.S. Trademark Office: http://www.uspto.gov/.

1. Enter the official website of the US Trademark Office. http://www.uspto.gov/, click "searching trademarks" under Trademarks.

2. No need to read in detail, click "searching trademarks" and choose the first query method;

3. Enter the trademark name you want to query in the "search term" column;?

4. For example, query: Alipay ALIPAY, registration status in the United States;

5. Click on the trademark that appears to display the trademark information. You can see its protection scope, submission date, acceptance status, etc. If it is 'LIVE', it means that the trademark is protected.