The relationship between EMS and USPS is the same as the relationship between the United States Postal Service and China Post. After foreign mail is sent to China through USPS, it is taken over by China Post and then converted to EMS. in the hands of users.

USPS packages are handed over to China Post after they arrive in China

You can check the arrival time in China at www.usps.com

Then you can On the ems website/enter your usps tracking number when querying ems package information to check the information after arriving in China

The U.S. zip code (ZIP Code) is the United States Postal Service (United States) A zip code used by the Postal Service (USPS), usually written in capital letters as ZIP. ZIP is the abbreviation of Zone Improvement Plan, which implies that mail can be delivered to its destination more efficiently and quickly. The most basic ZIP number consists of five numbers, with four numbers later added to allow mail to be delivered more precisely to its destination. The ZIP number after the added number is called "ZIP 4". The ZIP number was once registered as a trademark by the U.S. Postal Service, but its registration has expired