The palace is the largest complex discovered so far in the huge 22-square-mile mausoleum of the 2nd century B.C. emperor located on the outskirts of the ancient capital city Xi'an in central China, Britain's The Guardian reported Monday.
Eighteen courtyard-style houses surround a main building in the complex, estimated at about 700 yards long by 300 yards wide, Sun Weigang of the Shaanxi provincial institute of archaeology said.
The palace is clearly a predecessor to Beijing's Forbidden City, occupied by emperors during the later Ming and Qing dynasties, Sun said.
The foundations are well-preserved and archaeologists have reported finding walls, gates, stone roads, pottery shards and some brickwork, China's state-run Xinhua News Agency reported.
Qin's tomb is famously guarded by an estimated 6,000 life-size terracotta warriors, including remarkably well-preserved cavalrymen, chariots and horses.
The "terracotta army" was declared a world heritage site by UNESCO in 1987.