If you are the primary breadwinner in the house, doesn't that also make you the boss of it in your culture?
Tell your parents (respectfully), that while you appreciate their concern, you are a man now (bringing income into the house, etc) and that your personal relationships are your business.
Not that you should completely discount your parents opinion of who you bring home, but really, your GF sounds quite nice. Your parents sound kind of racist, frankly, and its not uncommon for their generation (if immigrants from China or Jpn) to be uncomfortable with their children getting serious about someone outside their culture. Its just fear of the unknown, really. Do what you can to reassure them without bending over too far backwards.
Its your life to live, not your parents. You have to live it the best you can.
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh