回复：请问拿不到绿卡被迫回国后, 孩子的美国公民身份是否会没

Depends on where you are. If you are in China, your kid will be Chinese according to Chinese law. Of course, she will have all benefits as other Chinese kids.
When she is 18 years old, she can choose what she wants. If she wants to be an american, she can apply for US passport in US Embassy or any Consulate using her birth certificate, according to US law.
Same thing applies if you go to Canada.