To meet the demands of enterprises in different developing phases, relevant software systems are implemented and applied. However, as the time goes, a number of software products increase, and many problems occur, such as previous system being inadequate to the new demands, the confusions for interaction and management among these systems, data redundancy, high cost of maintenance and so on. Previous systems, which were intended to help enterprise develop, however, turn out to be a retroaction. To solve these problems, a novel design of constructing enterprise information-based system base on SOA is proposed in this paper, which can be used to encapsulate the existing systems into services for reusing. This design puts forward a new idea for construction of enterprise informatization.