According to the Regulations of People's Republic of China (PRC) on Foreign Exchange Control, there is a limit for China citizens to bring foreign currency back to the Mainland from Hongkong. Specifically, each citizen can bring up to $5,000 worth of foreign currency cash into the country every year.

In addition, it should be noted that if you want to bring more than this amount of foreign currency cash into the country, you need to declare it to the foreign exchange administration department in advance and go through the relevant formalities at the designated bank. There are no restrictions on trade between Hong Kong and the Mainland.

In China, Hong Kong is a separate customs territory, and there are certain trade barriers between Hong Kong and the Mainland, but these barriers are gradually decreasing. The trade between the two places is mainly entrepot trade, that is, goods enter the mainland from Hong Kong and then are exported overseas from Shenzhen or Guangzhou. In addition, Hong Kong has also conducted some direct trade cooperation with other places in the Mainland, including procurement and investment.

Generally speaking, the trade between Hong Kong and the Mainland is less restricted, but some details need attention, such as customs declaration, inspection and quarantine.

To sum up, there is a limit on the number of Hong Kong dollars brought back to the mainland from Hong Kong, and each citizen can bring up to the equivalent of US$ 5,000 in foreign currency cash every year. If you want to bring more than this amount of foreign currency cash into the country, you need to declare it to the foreign exchange administration department in advance and go through the relevant formalities at the designated bank.

Legal basis:

According to the Regulations of People's Republic of China (PRC) on Foreign Exchange Control, citizens of China who bring more than US$ 5,000 (or equivalent foreign currency) into the country every year should make a written declaration to the customs.