The official name of the Chinese Currency is Renminbi (RMB), but is often named "Yuan" or "Kuai". The abbreviated written symbol for RMB is Yuan. Generally speaking, the largest denomination uses in daily life is the 100 Yuan note. Notes come in 1, 2, 5, 10, 20, 50 and 100.
In Tibet, only US dollars can be accepted apart from Chinese Yuan. Shops that can accept American currency are very limited and you may not be able to get a good deal for an exchange rate there. Major currencies can be exchanged for Chinese Yuan (CNY) at the Bank of China Branches at Gonggar Airport, Lhasa and Shigatse.
Credit cards can be accepted only in big cities in Tibet, like Lhasa and Shigatse. Most of the internationally accepted credit cards are usable in Lhasa, including Visa, MasterCard, American Express, Diner's club, and the JCB card of Japan. And they are accepted only in large shopping stores and hotels. Credit card symbols are displayed in the visible place in shops and hotels indicating credit cards are accepted. But, ATM is not widely available.