Abstract: As a major means of payment in the international trade,letter of credit (L/C) is regarded as "the blood of international bu siness".But by exploiting the characteristics of the transaction with L/C,some outlaws colluded together and fiercely committed cheating behaviors in all the operative parts of L/C,which caused a great economic loss to the persons who are entitled to the rights of L/C,affected the normal development of enterprises,brought about the damage to the bank's credit,destroyed the order of transaction,and endangered the L/C system.Therefore,each party should prevent efficiently the fraudulence in L/C.The paper discusses the principled measures and the technical measures on fraudulence in L/C.