Based on structural model of corporate bond credit spreads, this paper estimate MTNs credit spreads from credit risk measurement perspective. The result shows that: structural model factors show significant positive correlation to credit spreads. Through the empirical analysis, macroeconomic indicators,MTNs duration, credit rating, bond supply, companys operating leverage are considered. We find output target, bond rate are negatively related to credit spreads; while bond newly increased supply, longperiod and the equity multiply number of issuing entity are positively related to the credit spreads of mediumterm notes.