It is quite easy to exchange your currency into CNY at your arrival airports, as well as hotels and banks in China. You can exchange your currency and travelers check at the banks, banks' cash centers at major airports and hotels in Hongkong and China Mainland. Also, please kindly note that the there is about 4% card charge occur if you use your credit card. US dollars and Chinese Yuan are not widely accepted in shops and restaurants in Hong Kong. Although some shops do, their exchange rates might not be very favorable for you. You are suggested to exchange whatever currency you have into HK dollar at the banks when you are in Hong Kong.