Credit card pre-authorization refers to the transaction in which the card issuer or its agent confirms the permitted frozen amount before the deduction of the special merchant. Pre-authorization will occupy the credit limit of the card. When the customer settles the pre-authorization, the pre-authorization will be cancelled. Simply put, the pre-authorization of credit card means that the merchant freezes some funds before the cardholder spends, and after the cardholder signs, the merchant can formally deduct this part of funds. Generally speaking, it is a way of advance payment, which can be understood as "deposit" is mainly used for the guarantee when staying in the hotel. Generally speaking, the credit card pre-authorization period is 30 days. Within 30 days after the pre-authorization, if the customer fails to settle the account, the pre-authorization will be cancelled. However, the credit card pre-authorization freezes the credit card limit of the cardholder. If the cardholder does not cancel the pre-authorization of the credit card when leaving the store, the credit limit will continue to be frozen. For some cardholders with low credit card limit, this will affect their future credit card consumption. Therefore, when the cardholder finishes spending, it is generally best not to forget to cancel the pre-authorization of the credit card after checking out. After the pre-authorization of the credit card is cancelled, the credit card limit will be restored.