On the mainland, all currencies other than RMB are foreign currencies. Article 3 of the Regulations of People's Republic of China (PRC) on the Administration of Renminbi: The legal tender of People's Republic of China (PRC) is Renminbi. No unit or individual may refuse to pay all public or private debts in People's Republic of China (PRC) in RMB. Article 8 of the Regulations of People's Republic of China (PRC) on Foreign Exchange Control stipulates that foreign currency circulation is prohibited in People's Republic of China (PRC).

Hong Kong dollars and Portuguese coins (if you laugh to prove that you are not Cantonese, this name has been called for nearly a hundred years) were not originally issued in China. Although the two places are administratively subordinate but not financially subordinate, they are still self-contained. Taiwan dollar is caused by historical reasons and is self-contained. They can't enjoy the normal remuneration allowed by law. Foreign currency can not be simply understood as "foreign currency", but "currency other than local currency"