The aircraft, developed and built by the state-owned aircraft firm Aviation Industry Corporation of China, took off and later landed on the water in Hubei province's Jingmen, state-run China Daily reported.
The seaplane took off from the Zhanghe Reservoir at 8:51 am (local time) and stayed airborne for about 15 minutes, said the report which also accompanied the videos of the aircraft's take off.
The aircraft code-named Kunlong was piloted by four crew members.
Early this month, it completed its first water taxiing trials at a high speed of 145 kilometers.
Designed to be the world's largest amphibious aircraft, AG600 is powered by four domestically-built turboprop engines and has a range of 12 hours.
It will be mainly used for maritime rescue, fighting forest fires and marine monitoring, according to an earlier report by the state-run Xinhua news agency.
The aircraft has passed a series of tests since its maiden flight last December. It successfully finished eight taxiing tests on water at a speed of 80-kilometre per hour and 120-kilometre per hour.