KYC means know your customers in Chinese, including contents: most foreign anti-money laundering laws require natural persons, legal persons and other organizations, including accounting firms, to have a comprehensive understanding of their customers, that is, to know your customer principle. The main goal of "Know Your Customer" is to effectively find and report suspicious behaviors by verifying the customer's identity and understanding the business behavior, because unless you have a full understanding of the customer and can predict its business behavior, you can't reasonably and effectively find abnormal or perhaps suspicious behaviors from the customer's daily and habitual behaviors. Usually, after considering the business history of the enterprise, this kind of understanding is to obtain a complete understanding through an appropriate and diligent investigation on the beneficiaries of the transaction, the source and use of funds, and the appropriateness and rationality of the enterprise's behavior and transaction form.

According to the requirements of the Forty Recommendations of the Financial Action Task Force, the review procedures of the Know Your Customer Principle include:

(1) Confirm the identity of the direct customer, that is, know who the customer is or what the subject is;

(2) Reliable and independent documents, data or materials should be used when verifying the identity of customers;

(3) Confirmation of actual ownership and control-confirmation of which natural persons ultimately own and control the direct customers and/or actual beneficiaries of the transaction;

(4) Verify the identity of the actual owner of its customers and/or the actual beneficiary of the transaction;

(5) Conduct continuous due diligence and detailed inspection-conduct continuous detailed inspection on the transactions and accounts during the business relationship with customers to ensure that the ongoing transactions are consistent with the financial institutions' understanding of customers, their business and their risk status, and confirm the source of funds when necessary.

At present, the principle of knowing your customers is expanding to include "knowing your employees", "knowing your agents", "knowing your related parties" and even "knowing your third-party service providers". Experience shows that cheating employees and similar parties will help to implement and carry out money laundering.