Has anyone used a Chinese debit card outside the country or in Canada-does it work?
You're supposed to be able to use them at all ATMs that accept Discover cards - and apparently Interac in Canada, whatever that is: https://en.wikipedia.org/wiki/China_UnionPay
The Union pay card? Some have worked in Canada and some have not. You have to make sure your bank gives you a card that can be used internationally.
Union Pay is huge and growing, sure you can use it at Canadian AMTs, the question is fees. Judging by Canada's demographics I would be surprised if Canandian banks would partner with Chinese banks, check who's the Canadian or Chinese partnerbank to avoid high fees. A lot of Chinese banks would probably also have branches in Canada.
I tested my CCB card at a Bank of America, and it worked. Those two do have a special relationship though. I think some Chinese banks have one or two branches in US now, Canada maybe? The thing about Discover should be true as Discover and UnionPay do have a relationship, but it might be only for credit and debit cards.
edit: be only for credit and not debit cards.