The tombs, which date back to the Han Dynasty (202 BC - AD 220), were discovered at the Ma'anshan Tomb Site on the bank of the Yangtze River, state-run Xinhua news agency reported.
Archaeologists have found more than 430 artifacts in the tombs, including pottery, bronze and iron ware, it said.
The tombs and artifacts will help archaeologists gain a greater insight into local customs, as well as social and economic conditions during the Han Dynasty, the report added.
The Three Gorges Reservoir is the biggest dam in China built on the the country's longest river, Yangtze.