Can paypal's US account be transferred to China users by private mail?

yes, the gift method is limited to non-commercial payment, one-way payment, and it is not easy to complain and withdraw later. A few years ago, it was also available in China, but many people in China used gift to do business, and paypal later cancelled the function of China account. Pay attention to safety, it's okay to use it once or twice occasionally, but you can see it when you use paypal too much, and you will be punished for being clever.