The consequences of owing a credit card debt of RMB 20,000 and being overdue for one year are serious. First, the bank will take a series of collection measures to recover the arrears. Secondly, overdue records will be reported to personal credit reporting agencies, which will have a negative impact on personal credit scores. Finally, there may be consequences such as legal proceedings and property execution.

Specifically, the following is a detailed explanation of the conclusions given:

1. Collection measures: Banks will collect collections through phone calls, text messages, letters, etc., requiring repayment. . They may also contact your employer, relatives or friends to urge you to repay the loan. If collection efforts are ineffective, the bank may transfer your account to a specialized collection agency or law firm for further processing.

2. Credit record: A debt of RMB 20,000 overdue for one year will be recorded in the personal credit report and have a negative impact on the personal credit score. This will affect your credit evaluation results when applying for loans, credit cards, house rentals and other related financial services in the future, which may lead to difficulties or rejection.

3. Legal proceedings: The bank has the right to recover the arrears through legal means. They can file a lawsuit in court and apply for enforcement measures to recover the money they are owed. If the court rules in favor of the bank's claim, you may be required to assume a higher amount of debt and may have your personal property seized or auctioned to repay the debt.

Summary: Overdue debt of RMB 20,000 on a credit card for one year will cause the bank to take collection measures, personal credit will be damaged, and you may face legal proceedings and property execution. Therefore, it is important to pay off your credit card balance promptly to avoid these harsh consequences.

Extended information: According to relevant laws and regulations in China, banks are bound by law when collecting debts and cannot take excessive actions, such as threats, intimidation, violence, etc. In addition, according to the "Consumer Rights and Interests Protection Law of the People's Republic of China", banks or collection agencies must also respect the legitimate rights and interests of consumers during the collection process and comply with the procedures prescribed by law.

However, the above only provides general answers. The specific consequences are also affected by many factors, such as the amount owed, overdue period, bank policies, etc. It is recommended that the parties concerned communicate with the bank in a timely manner and negotiate on repayment issues to reduce possible negative consequences.