I'm taking a flight that's transferring in China, then

>>1217775
Depends. If you're planning to ask what it depends on, then answer is "on God knows what". Sometimes I had my luggage go all the way through to the final destination, sometimes I had to spend four hours in immigration queues. Even on return flights. Welcome to China, the land of the bureaucratic unknown.

you need to pass through immigration and get your passport stamped, yes. and then you will need to go through a security checkpoint again.