The reserve fund of rural commercial banks refers to a form of credit loan of rural commercial banks, which can also be regarded as the "installment payment" line of credit cards. Under normal circumstances, the amount of petty cash will not be included in the total credit card. If the borrower uses the reserve fund for installment consumption, the consumption bill will be merged into the total credit card bill, and the borrower only needs to repay it together with the credit card debt.