The coins were found in 3,000-year-old coin pits in the ancient town of Huoluochaideng, Lian Jilin, a researcher with the regional Institute of Cultural Relics and Archaeology, told China's state-run Xinhua news agency.
Most of the hoard was "Huoquan" coins, commonly used in the Han Dynasty from 202 B.C. to A.D. 220, Lian said.
Archaeologists said they also unearthed more than 100 casting molds from the relics of a coin workshop dating to the rule of Emperor Wudi, 156 B.C. to 87 B.C.
The cultural relics found in Huoluochaideng, the evidence of extensive coin production and the size of the city's ruins suggests it was a major town in northern China during the Han Dynasty, Lian said.