The tomb was uncovered in Yangzhou City in east Jiangsu Province, China's state-run Xinhua News Agency reported Tuesday.
Evidence suggests it's that of Yang Guang, or Emperor Yang of Sui, the second and last monarch of the short-lived Sui Dynasty (581-618), the Yangzhou City cultural heritage bureau said.
A gravestone found the tomb carried the emperor's name while an inscription with the year of his death concurred with historical accounts, Shu Jiaping, head of Yangzhou's institute of archaeology, said.
"But we're still not sure whether it was the emperor's final resting place, as historical records said his tomb had been relocated several times," Shu said.
The tomb was discovered at a construction site connected to another tomb archaeologists said might belong to the empress.
Yang Guang is considered a tyrant in China's history for forcing millions of workers to build palaces, luxury leisure boats and the Grand Canal, which was later lengthened to connect Beijing and Hangzhou in the world's longest artificial waterway.
Yang Guan was killed during a mutiny in A.D. 618, which toppled the Sui Dynasty and may account for the relatively small size of his tomb, researchers said.