Abstract: Traditional application integration is of closed coupling mode by nature,which reduces the flexibility and extensibility of business system,increases difficulty in maintenance and impedes the adjustment and optimization of business flow.Therefore,the SOA-based integration of discrete information systems in manufacturing industry was introduced by taking Shanghai Tobacco Machinery Company Limited as an example.By the character and advantages of SOA,and making use of the architecture of service bus in place the business flow was integrated by the implementation of SOA application mode based on Web service.The application results indicated that SOA mode could effectively avoid the generation of redundant data in various application systems and achieve more fluent communication between different systems and flexible restructuring of business flow between discrete application systems.The integrated system turns the business flow from an isolated point-to-point and repeated status into a low maintenance cost,high utilization and sharing service one to better meet market demands.