Can I use Guangzhou Transportation Smart Card in another city of China?

Yes, if you get a Yang Cheng Tong, you can use it in GZ and Foshan. If you have a Ling Nan Tong, Octopus Card (Ba Da Tong) card, you can use that in GZ city and Hongf Kong. Besides, there are other combined cards that can be used in GZ and other cities in Guangdong province.