The base unit of Chinese Currency is the Yuan , formally called the renminbi (CNY) and colloquially known as kuai. One yuan is divided into 10 jiao or mao. One jiao is divided into 10 fen, though these last are effectively worthless.
The current exchange rate is approximately:1.00 EUR = 9.2599 RMB , 1.00 USD = 6.4399 RMB
The best way to carry your funds is by traveler's checks, which are available through banks and travel agents in major cities of China. Their exchange rate in China is fixed and in fact better than for cash, and they can be restored if you lost them.
Credit cards are useful too. Visa, American Express, and MasterCard are the more accepted cards at big tourist hotels. In Hong Kong, Shanghai and Beijing some ATM machines accepts Visa cards.