The official currency of People's Republic of China is the Rénmínbì. It is legal tender when you visit mainland China, but not in Hong Kong, Taiwan or Macau. Rénmínbì literally means ‘People's Currency'. This guide will help you understand better Chinese Renminbi Denominations better.
The basic unit of Chinese money is the Yuán. One Yuán is subdivided into 10 Jiǎo, which in turn is subdivided into 10 fēn. The Yuán comes in paper notes of 1, 5, 10, 20, 50 and 100 Yuán notes, and 1 Yuán coins. The Jiǎo comes in coins of 1 and 5 Jiǎo. The fēn has been phased out and for all intents and purposes, no longer exist.
It is important to understand Chinese Rénmínbì denominations as China is mostly a cash only country, and it will help with your travels. Nearly all transactions are completed with cash, most shops have a note counter and cashiers will check your notes for fakes (which I'm told is a big problem). When we registered for our language course we had to pay with a large stack of 100 Yuán notes. There are plenty of cash points around, although whether or not they will accept your Visa/whatever is another problem entirely. Generally speaking, a Bank of China ATM is your safest option. Most shops, even Western brands, will not accept anything but China Union Pay so don't rely on your Visa or Mastercard whilst travelling here.
In Chinese there are many words that are used in Spoken Chinese that are different to ones that would be used in Written Chinese for the same thing (just to make things more fun). This is true for the Chinese Rénmínbì denominations. If you are looking for a quick way to check currency rates, visit XE.com for the latest rates.