本研究乃先從探討美日評等機構之評等著手，並根據深入訪談國內信用評等機構 、債券承銷商及發行公司，歸納出債券評等的考慮因素，以此因素，利用區別分析，建構出 客觀、數量化的區別模式，以作為債券評等機構決定初步等級的參考。

　　　　　This research investigates the ranking system in American and Japan at first. According to the opinions of ranking institute, underwriter and issuing company, we can generalize the ranking factors. This research uses these factors to establish a discriminate model. We can use this model to rank the corporate bond.