Abstract: The capital system arrangement of the Company Law should be based on the transaction nature of the company, fully respect the business logic and the market logic, and analyze the contracting process between the commercial subjects such as shareholders and creditors. On the premise of minimizing social costs, the welfare of all parties should be improved. However, the reform of corporate capital system in 2013 expelled the creditors of small and medium-sized enterprises into the blank area of the system. The perspective of transaction costs can help us to better recognize the hidden risks behind this institutional changes, dig out the economic structure behind the corporate law, and understand the complex relationship between institutional design and the real business mechanism. To observe the changes of China’s corporate capital system in the past twenty years from this perspective can help us better regulate the moral hazard behavior of the shareholders, at the same time, view the pros and cons of the current reform of the corporate capital system more objectively.

Key words: corporate law economic structure; transaction costs; corporate capital system; contract of creditor’s rights