Yes, you can use Chinese currency (renminbi/yuan) in Hong Kong, but there are important restrictions to keep in mind.
The People's Bank of China (PBOC) caps the amount of Chinese currency that can be brought into Hong Kong at 20,000 yuan per person per day. Exceeding this limit requires declaration and may incur penalties.
Not all businesses in Hong Kong accept Chinese yuan. Many retailers, restaurants, and service providers only take Hong Kong dollars (HKD). Others accept both currencies, but the exchange rate they apply may be unfavorable. Always confirm payment options before making a purchase.
For the most favorable rates and to avoid hassles, convert your yuan to Hong Kong dollars before traveling or immediately upon arrival at banks, licensed money changers, or ATMs. This ensures you have the local currency widely accepted everywhere.