Istanbul-Beıjıng-Guanjou-Melbourne

I suggest getting a visa in advance, people have been refused visa free transit with Turkish passport stamp

I am not Turkish, I am just travelling via Turkey. I am Tajikistan citizen and have tajik passport. Will be still problem there ?

Have you been to Turkey before? If yes then you risk being refused entry at Beijing if not holding a transit visa. The more likely scenario however is that the airline will not let you on board and use the fact that you don't have a visa as an excuse.

Yes I have been in Turkey but why does it matter if I am not Turkish?

Daler, in reality, your itinerary is eligible for 24 hour visa free transit and in ideal conditions there should be no problems as far as your transit through China is concerned. Also, I would say that you would travel through China without any significant problems in 9 out of 10 cases. Anyway, because of this 1 in 10 cases and because of the fact that China is blaming Turkey for the radicalization of Uyghurs (Xinjiang province) in both religious and nationalistic aspects, Chinese immigration is from time to time suspicious about the people who have Turkish stamps, have lived in Turkey or are related with Turkey by more or less strong bonds. Exactly this is the cause why two valuable contributors of this forum have expressed their concerns that in some circumstance you could be denied the continuation of your journey toward Australia and forced to return back.

I cannot say that something negative will happen, but maybe a transit (G) visa would bring you a peace of mind, although I understand the entire hassle of the visa process and the wish of almost everybody who can, to bypass this boring, money and time consuming process. Anyway, in your case, this could be an investment.