"CHINESE CONTRACT RULES"

To answer your question about 30 days notice, yes. They can cancel your contact without warning. Most reputable businesses will not do this unless you did something against the rules.

To protect yourself, make sure the Chinese version of the contract is the same as the English version, and keep a copy for yourself. If your company obtains the Foreign Expert Certificate, ask to keep it yourself. Even if they get a regular working permit, keep it. This will make it harder for them to cancel your visa without warning. You can also try to negotiate a longer warning period.

If your contract is terminated for non-criminal reasons, you will have a 30 day tourist visa issued to you (this is the law). This gives you time to find a new job or make arrangements to leave.

Many thanks mond5004 for your tips!

In fact Chinese contract labor has different rules than in Europe...
I will sign a contract where it is both written English and Chinese... I don't think that I could request to the company to erase the Chinese translation under each paragraphes of my contract... isn't?

Also, I have negotiate a 2 month notice and asked them to add this comment : "ONLY IF" breaches... in the contract.

Correct. You can't remove the Chinese words from the contract. In the event of a legal dispute, the Chinese version takes precedence over the English version.

Like I said, the majority of Chinese companies will treat you very well. They won't just fire you or terminate your contact unless something is very wrong. When your contact is done, they will offer for you to sign a new contract. If you decide not to sign again, you will still get the 30 day tourist visa.

Many thanks for having reassuring me! ;-)
I keep my fingers crossed hopping everything will be fine...