Since corporations show heterogeneous features when progressing in life cycle, it's been crucial for creditors to build dynamic governance mechanism not only for the safety operation of regional finance, but for the governance balance for the corporations. Based on corporations' dynamic capabilities theory, after separating different phases of life cycle by using China's private list corporations' data, this paper analyzes the creditors' dynamic influence upon agency cost in every phase of their life cycle. It is found out that agency cost shows a "vibration" phenomenon as corporations proceed in their life cycles, and the ones in mature phase have the highest agency cost level. Short-term debt from creditors has shown dynamic governance effect towards agency cost, while long-term debt can amplify the agency cost. Both dynamic governance and amplifying effect increase marginally when the corporations proceed in their life-cycles.