Hi All,I was wondering how much does cost me to send 38Kg parcel from china to Australia? (CHEAPEST)

Jing, I'm afraid you need to send it as two parcels, for each package is not allowed to exceed 20kg according to the rule. For two parcels of 20kg and 18kg, you should pay about CNY720 via surface mail. If this item cannot be sent separately, you may deliver it as a cargo.

Thanks Birrell for your reply,
does is have a tracking number as well? and how long do you think my items will be delivered?
and in total, is there as risk of not being delivered?!

Yes, you will get a tracking number. Surface mail is the slowest and it should take around one and a half months to get to Australia.
The chance of the parcel being lost is very slight. You don't need to worry about it.