Is it still possible that my wife get H1b apprved after she go back to china and apply this position again?
-Yes. She had better use premium processing to get the h1 approved in 15 days. If her H1 approval has no I-94, she just goes to China to get the H1 visa to come back. After she gets the h1 status, you may go to China to get the H4 visa to come back.
By the way, because F1 I-94 is D/S (Duration of Status), you will not be sujected to 3 or 10 year bar by this point.