Trading Bitcoin and other crypto-currenices is a criminal activity, China's central bank says.
"Virtual currency-related business activities are illegal financial activities," the People's Bank of China said, warning it "seriously endangers the safety of people's assets".
China is one of the world's largest crypto-currency markets.
Fluctuations there often impact the global price of crypto-currencies.
The price of Bitcoin fell by more than $2,000 (£1,460) in the wake of the Chinese announcement.
It is the latest in China's national crackdown on what it sees as a volatile, speculative investment at best - and a way to launder money at worst.