Korean and Taiwanese?! Geez, it's not about "race"..

Maybe the parents are afraid… that they wouldn't be able to communicate well with her, and/or they wouldn't be able to influence/control his son's (adult) life.. exactly same as some Korean parents :p

I think "winning them over" might take quite some time. Not rushing might work better. Afterall, the couple themselves are the decision makers; the parents can express their dissatisfaction as much as they want, but they won't be the do-ers, right? I agree with Utah not Mormon; the boyfriend's role must be crucial as the bridge between his parents and his partner. It's him who really knows his parents too… and, well, I also tend to think that this crisis (for the lack of a better word) could be an opportunity for her to get to know her partner in a deeper level. Like, see how he's doing between his parents and her. Also…. I'd like to suggest her to try to understand his parents. There must be reasons other than "race" or a different nationality. Probably they are the baby boomer generation, with their specific expectations and beliefs, and their son's relationship with her must've been a sort of shock to them. Be compassionate and give them some time.. :)

Hope she can relax a bit and cherish her relationship without much distress!