Chinese Visa if enter in Guangzhou

Visa is not required for you to transit in GZ for a stopover less than 72 hours from June 1, 2013. BTW, if you want to visit GZ city during stopover, you can simply apply for a stay permit at Baiyun Airport.

Thanks your reply, I am not sure what is stopover. Can I visit Guangzhou during that time.
I am leaving Hong Kong on September 28, 2013 and take a flight on September 30, 2013 2:00 pm. to America via Canada.
Do I need a visa? What can I do? Thanks

Stopover means transit layover at airport. You can visit GZ during this time, but you need to apply for a stay permit at the airport. Visa is not required, just prepare your valid passport, and confirmed ticket to US via Canada for the permit application. Tell your transit request to the airline first, then you will need to fill a form before boarding the plane to GZ. The permit will be issued upon arrival at the airport.