How long can I stay in China with a tourist visa? I am planning a 80 days roundtrip

It depends on the stay duration of your tourist L type and the stay duration is 30 days in most casesand it means that you can stay in PRC for 30 days. But sometime, one may get a tourist L type with stay duration of 60 days. The consular officers may give you proper stay duration according to your travel itinerary.