Explanation
Yes, in terms of its official national standard. China uses Beijing Time, also called China Standard Time, at UTC+8 across the country.
Beijing's official government portal states that the whole country adopts Beijing Time. The independent timekeeping reference Time and Date confirms the single official time zone and reports that China currently makes no daylight-saving clock changes.
Official standard time does not describe every local practice. In Xinjiang, some residents also use Xinjiang Time, or Ürümqi Time, two hours behind Beijing. The claim is therefore correct about the national standard, but should not be read as saying every clock or daily routine follows it.
Key takeaway
China has one official national time zone, although a different local time is also used in Xinjiang.