It is legal for China Merchants Bank and Taikang Life to charge credit cards.

According to the "Contract Law of the People's Republic of China", contracts concluded by the parties should follow the principles of voluntariness, equality, fairness, good faith and good faith. There may be a cooperation agreement between China Merchants Bank and Taikang Life, which allows China Merchants Bank to deduct credit card funds to pay Taikang Life's related expenses with the cardholder's consent. This type of cooperation is relatively common in the market and complies with the provisions of contract law.