Answer:

China's legal tender is Renminbi (RMB). Foreign currencies can not be used directly in China, though some shops illegally accept foreign currencies.

The basic unit of RMB is yuan. 1 yuan (or kuai) =10 jiao (or mao). RMB is available in both paper notes and coins. The denominations of paper notes are 100, 50, 20, 10, 5, 2 and 1 yuan; 5, 2 and 1 jiao. The denominations of coins are 1 yuan; 5, 2 and 1 jiao. The symbol of RMB is£¤ Hong Kong uses HK dollars.
Foreign currencies may be converted into RMB at all banks, bank branches or hotels at the exchange rate quoted on the foreign exchange marker on the day.

Black market in foreign currency is forbidden in China. People may approach you in front of hotels, at tourist spots or at banks for a black market exchange. You should be extremely careful. The exchange rate may be attractive--higher than the bank rate--but it is illegal and you risk being cheated. Sometimes these people don't give you the right amount, since you don't have time to count the money or, even worse, they may give you fake notes or a bundle of plain paper with a few notes on the top.

When you exchange money at the banks, you should ask for a certificate, with which you can change RMB back to foreign currency when you leave the country.

The Bank of China is the bank which specializes in handing credit cards issued in foreign countries. They include Visa, MasterCard, Diner's Card, American Express, JCB, Million Card and Federal Card.
These cards can be used at major hotels and shopping centres where the Bank of China has branches. In the event that you lose your card, you should report to one of the branches of the Bank of China and apply for a replacement.

The Bank of China has an agreement with foreign financial organizations on selling, cashing in and compensating for traveler¡'s cheques.

The official exchange rate at this time is 8.1 yuan to 1 U.S dollar. Keep the receipt of the transaction as you might need when you leave China to change your US dollars back in Bank of China at the airport.