by using the case of the investment audit of information system engineering by the experts of the external information technology, this paper explores the audit method of implementing the investment price evaluation for the software development project of the public hospital information system. It uses the audit results to establish the long effect mechanism, formulating the contract template for the development of the information system, obtaining the intellectual property right of the software development, and introducing the supervision service. We should strengthen the whole process quality management of software development companies and form a new mode of information system investment audit.