Legal analysis: Adults cannot change their names and surnames to neither their father’s nor their mother’s surname. You can change your name by yourself when you are over 18 years old, but you can only change it once in your life. According to the "Name Registration Regulations of the People's Republic of China", citizens should take their father's or mother's surname, but they are allowed to adopt the surnames of both parents. When a child adopts the surnames of both parents, they can be named according to both surnames, but it will not be counted as a compound surname.
Legal basis: "Regulation of the People's Republic of China on Name Registration"
Article 3 Citizens should take their father's or mother's surname, but they are allowed to adopt the surnames of both parents. When a child adopts the surnames of both parents, they can be named according to both surnames, but it will not be counted as a compound surname.