You can't. Credit cards can only be used for the consumption of goods or services in legal fields, and cannot be overdrawn for any investment activities, including securities investment, real estate investment and precious metals investment. So they are not allowed to buy gold. According to Article 7 of the Measures for the Supervision and Administration of Credit Card Business of Commercial Banks, credit cards refer to all kinds of media that record the relevant information of cardholders' accounts, have the functions of bank credit line and overdraft, and provide relevant banking services for cardholders.