Until July 1, 1996, no international rules, other than the simple practices contained in the UCP 500 have existed for the processing of bank-to-bank reimbursements. At last, ICC Uniform Rules for Bank-to-Bank Reimbursements under Documentary Credits(Pub. No. 525) have been published on July 1, 1996. Our country have adopted the URR 525 on August 1996. But in view of the present number of countries adopted the URR 525, I think our country is very impetuous. In order to comprehend the URR 525 correctly, this study is carrying out to clarify the legal principles on reimbursements among issuing banks, nominated banks, unauthorized banks. Secondly, this study is carrying out indicate the background of establishing, the main contents, the approval and the criticism of URR 525. Finally, this study is carrying out to point out the matters that demand special attention about the operation of URR 525