From what you wrote, it sounds like your father is no longer around, and maybe that's where the problem lies. Your mother is associating your Chinese Girlfriend with your Chinese Father (albeit all 1/4 of it). She needs to get over the fact that not all Chinese people are gonna act like your father. I think somehow she is venting her frustration on your father but directing it at your girlfriend. She's probably not a "out and out racist", But she clearly has crossed the line and you need to resolve this now, before things go too far. If you didn't live at home you could just "lay down the law" and tell her where to get off, But as it is living under her roof, she can make your l;ife uncomfortable if not unbearable. Best thing to do is get out and get your own place, even if its a house share, its better than what your currently having to put up with. I know they say "blood is thicker than water", But in a situation like this, where love is involved, the mother is usually the one to lose out, I'd stick by my wife every time. I think almost everyone goes through something like this at one time or another, most parents can be intolerant of their son's/daughters choice of partner, But if your serious then you have to make them understand that their intolerance may some day drive you away, which someday could ultimately mean your children have little or no contact with their grand parents, So you have some choices to make, and some hard decisions.