Do you have chinese passport?

To Mr. Levi

I have australian passport as China doesnt accept dual citizenship
thanks.

If you have Chinese passport, you wouldn't have to apply for a visa anymore.
If not, you will have to apply for a work visa, but you have to find a job in China firstly.

To Mr. Daniel

does a working contract from a certain company is enough for applying for the visa?what else do i need to get a working visa?

You also have to ask your emplyer in China to provide you a Visa Notification Form issued by Chinese authorized unit and Working Permit issued to foreign experts by The State Administration of Foreign Experts Affairs, Alien Employment License of the People's Republic of China issued by Ministry of Labor and Social Security, Letter of Invitation for Foreigners Engaged in Offshore Petroleum Operations in the People's Republic of China, etc.