When a bank repays a loan in loans overdue, it should pay interest first and then the principal. This is because according to the agreement of the bank loan contract, overdue repayment will generate penalty interest. When repaying the loan, the bank will calculate the overdue principal and interest separately, charge the overdue interest fee first, and continue to calculate the interest until the overdue principal is paid off.

Specifically, there are several reasons why overdue bank loans should be repaid with interest first and then with principal:

1. Contract Agreement: It is generally stipulated in the bank loan contract that overdue repayment will result in penalty interest. According to the contract, calculate and pay off overdue principal and interest respectively.

2. Give priority to protecting interests: By paying interest first and then the principal, the bank can protect its own interests to the greatest extent and ensure that overdue borrowers pay interest. This can avoid long-term overdue interest payments and reduce the risk of banks.

3. Continuity of interest calculation: overdue repayment will make the bank recalculate the value date. If you don't pay the overdue interest first, and then calculate the interest after paying off the overdue principal, it will break the interest calculation, which is not conducive to the continuity of the bank's interest execution.

In short, overdue bank loans should be repaid with interest first, and then with principal. This can protect the interests of banks and maintain the continuity of interest calculation of overdue loans, which is also based on the principle agreed in the contract.

Extended data:

According to the Measures for the Administration of Commercial Bank Loans issued by CBRC, once a bank loan contract is overdue, it is necessary to continue to pay overdue interest at the interest rate agreed in the contract. If the overdue time is long, the bank may take collection measures for the overdue principal, such as entrusting a lawyer or a collection agency for legal recourse. Therefore, timely repayment is an important measure to maintain your credit record and avoid unnecessary losses.

It should be noted that the above answer is based on the assumption under normal circumstances, and whether the principal or interest should be repaid depends on the loan contract signed between the bank and the borrower. The specific operation methods of banks may be different, so in specific circumstances, it is still necessary to consult the professionals of banks or related institutions to obtain accurate information and suggestions.