Contract management is the core of management business that implements enterprise risk management and internal control. The quality of contract management directly affects the success or failure of the company's operations. However, the contract approval process of manual management is not clear: the level of information utilization is not high, resulting in low business processing efficiency with wasting huge man-power and material resources. Hence, many companies have been working on finding a simple and practical software to manage contracts. The article advances an electronic contract management software. The existing electronic contract system is not secure enough in encryption because of the shortcoming of easily forgetting and pretending. The new system adds a private key login through a coin-free open chain technology which is used in hospital, government, military, university and other special scenes, achieved perfect security guarantee. This paper discusses several crucial mechanisms implemented for the goals of designing the system, and gives out relevant methods and process of the implementation. Guided by system engineering theory, this thesis also discusses the modeling and optimization problems of consensus mechanism. The article finally makes analysis on the research process and results, discusses the advantages and prospects of the technology, and points out problems remaining to be solved.