The Tibet Branch of the Bank of China. [Photo/Baidu.com]

Banks in Tibet
There are three banks in Tibet: Bank of China, Bank of Agriculture & Bank of Construct.
Foreign Currency Exchange
The circulated currency in Tibet is RMB. Foreign currency can be exchanged in the banks there. All the branches of the Bank of China in Lhasa and other cities provide such services. But only the main offices of Bank of China accepts traveler's check and cash advance.
Lhasa Hotel and Tibet Hotel offer foreign currency exchange services too. You can exchange money into RMB according to the exchange rate of that day with your valid passport.
Visiting remote areas in Tibet, you'd better have enough RMB with you. But you can have some US dollars with you too.

(Edited from Tibet Tour )