When can China citizens immigrate to Australia after China citizens and Australian citizens get married in China?

You can apply for spouse immigration after marriage, and get permanent residency after approval, commonly known as P.R. The trial process takes about 18 months. If you apply in Australia, the time will be shorter. If P.R. succeeds, you will get the right to work full-time and invite your parents to visit Australia.

As for naturalization, you have to wait until you have lived in Australia for three years (the legal residence period before P.R. can also be counted, but there must be a one-year residence period after P.R.) before you can apply, and you will become an Australian Chinese after a simple examination and oath.