Apple's overseas kt version can be used in China. It will be very uncomfortable to use, see if there is a network lock. If you have a mobile phone with no network lock, and China has the same standard network as the United States, you can use it. If there is a network lock, it will not work. The locked machine only supports its custom carrier's SIM card. There is a big difference between foreign mobile phones and domestic mobile phones, but it is not a big problem to use foreign versions of Apple mobile phones.