信用证是国际贸易活动中常见的支付手段之一，因其以银行信用代替商业信用，能保障贸易双方的正当权益，降低信用风险，减少贸易成本，而成为国内外广大厂商的首要选择。海关在审核进出口报关单据的过程中，可能会更多地发现，利用信用证及其项下单据进行的商业欺诈、瞒骗行为 L / C is one of the common means of payment in international trade activities. It is the first choice for many domestic and foreign manufacturers because it can replace the commercial credit by bank credit, protect the legitimate rights and interests of both parties, reduce credit risk and reduce the trade cost. During the process of examining and approving import and export customs declarations, the customs may find more evidence of commercial fraud and deceit by means of letters of credit and the documents under the same.