No, the OP does not need to enter China for check-in with AC. TG will check bags to final destination. So you need to transfer at PVG rather than enter China - I have no knowledge of transfers at PVG so I will not make any comments on that.

TPJ is correct in the sense that ATC related delays are frequent in China, so there is a risk that your incoming TG flight will arrive late. I suggest to monitor the performance of TG 664 so you will get a better impression on the risks involved

PS: I just checked for you. For the past week TG 664 has arrived late every single day, ranging from delays of 5 min to 1:27 min. The duration of the flight vary between 4h 15min to 5h 27min - so this flight is very prone to ATC delays enroute.