Will I require to have visa in this scenario?

Hi there,
I am Nepalese Citizen (Australian Permanent Resident) travelling from Sydney-Kathmandu on 16 Sep and returning back on 5th Oct. My iternary reads as follows
Sep 16. - Sydney-Chengdu (less than 12 hrs transit in Chengdu)
Sep. 17 -Chengdu-Kathmandu

Oct 5 - Kathmandu-Chengdu and Chengdu- Beijing (change of airplane/different flight)
Oct 6 - Beijing- Sydney( less than 12 hours overall transit time in Mainland China)

I shall be thankful for the information.

RAJ