Does a Nepali citizen need to have a visa for China while they have a transit in China

Hello. I'm Suraj Nepali a citizen of Nepal. My wife is an Australian. My wife and I are flying to Kathmandu Nepal from Sydney Australia via China with China Southern Airlines. We have one stop (transit) in China.

1.So, do I need to have a visa for China already?
2. If I do need to have it for China, what type do I need to apply for?

I would be so greatful.
Thanks.