Is there any hopon hopoff bus in Guangzhou?

Yes, and there are three routes of the buses. The red bus is called ancient city line and starts from Baiyun Mountain General Bus Station; the yellow one is city axis line and leaves from GZ Tower General Station; and the blue is the Xiguan line and leaves from Shangxiajiu Pedestrian Street General Station.
As I know, there is no two-day ticket, and it takes CNY30 for 24 hours.