As a Chinese woman here, I think I know something about this issue. Family unhappy for your marriage maybe is caused by: (1) they think their daughters are excellent, and nobody can match with her, which is similar as American movie “Meet the Parents”; (2) they want to give hardship to their future son-in-law and let him to know that their daughter has strong back-up from family, and don’t bully her in the future. (these two points are suitable for Chinese son-in-law too.) (3) they distrust the seriousness of their future son-in-law, especially for American guys, as so many Hollywood movies and rumors make Chinese having the thought that Americans are easy to divorce (even China now divorce rate is more than 40%, but most of Chinese think American guys are not as responsible as Chinese guys in the family). (4) they like big and close family and dislike you taking her daughter away from them.
Then you may need to know what reasons they are unhappy firstly, and try to find solution. Also it is right marrying with a Chinese woman a kind of like marrying with her whole family. So It is hard for your Chinese finance to make decision to just be with you without her family where she was raised up.
Here is some my personal ideas and see whether they can help you:
(1) A gift is good ideal.
(2) Use some translation stuff. When my finance communicate with my parents, if I were there, I can interpret for them; but if I were not there, he said he can communicate through voice translation of IPhone and his body language; even the machine translation and body language sometimes are really wrong and funny, but really helping to break ice and easy the atmosphere.
(3) Let them to know you are really serious for this relationship, so maybe you need to ask to hold a family meeting or talk this at dinner when everybody there. You need to tell them you love their daughter and will try your best to make her happy. Majority of Chinese are shy to say this kind of words, but they love listening to this, and this will really help them to repel worries.
(4) Talk with them and let them know their daughter just going to US with you and she still can come back to visit them when you have chances….. Trying to help them to feel that they don’t lose a daughter, actually gain a more man (son-in-law) to be the member of this family.
These only my personal ideas. Every family is different. E.g. my family never has this issue, as my parents try to be democratic with their kids, and only we are happy, and they will be happy. Also I train them to accept diversity and difference.