As China has been regulating the management of engineering construction market, and due to the increasingly intensified competition of supervision market and also the self-demand of company’s sustainable development, engineering supervision companies have turned to adopt informatization to improve the management and competitiveness. Adopting mature integrated management information system could be an effective means to refine the management. With the development of Changke Supervision Company’s OA system as an example, we expound the demands of business processes, system performance, permission setting and other aspects. On this basis, we introduce the target, structure, main functions, and key technologies of the system. The system adopts work flow to realize company management informatization including document flow, business processing, management decision, etc. It has gained good result in practical application.