In in Tibet, ATM service is not easily accessible. In the cities like Lhasa, Shigatse, Tsedang, Baiyi, Lhatse, Zhangmu, Saga, it will be better if you visit with cash for the trip in Lhasa and other cities. The reason behind this, ATMs in small cities may work or may not work. Besides, the number of ATMs are quite a few in small cities, for example, there is only one ATMs in Lhatse, in case it is out of work, you cannot find an alternative.
Credit cards are a convenient payment method in Lhasa, but do not work well in other cities in Tibet. If you are staying in star hotels as four stars, five stars even 3-star hotels in Lhasa accept credit card. As they usually charge you 3-4% extra bank charge.The only bank that offers credit card is the Lhasa branch of Bank of China. You can get cash by ATM of the bank of China with a 3% commission and withdraw at most RMB 2000 cash.