I plan to fly from Kashgar to Shenzhen, at Lanzhou Zhongchuan Airport T2 to T3, The transit time is 1 hour and 40 minutes, is it too late?

Zhongchuan Airport only has T1 and T2 terminals, no T3. In addition, even if you are not in the same terminal, 1 hour and 40 minutes is enough if the plane is not delayed. But if the onward flight is delayed, say, by two hours...

If the plane is not late, it will be in time.