Abstract-The exponential evolution of technology and the environment surrounding the information systems (IS) forces companies to act quickly to follow the trend of business workflows with the use of high computer technologies and well adapted to the needs of the market. Currently, the performance of information system is considered a problem, we must intervene to make them more agile and responsive to better support the strategy of the company. The exchange and communication is a must between information systems to address these issues and new requirements, businesses are looking to integrate and interact even their information systems to interconnect applications. Interoperability is essential between information systems, it promotes alignment between the company's business strategy and IT strategy while respecting the existing technical heritage of the company. The interoperability solutions between information systems face major problems since the SI is independently developed and designed differently and that solutions must meet certain criteria, namely, autonomy, scalability and resolve trade problems of data. The MDA approach is the most suitable solution to our problem because it ensures a degree of independence between the logic the company's business and technology platform. Moreover, oriented architecture SOA service is used in this sense, it encapsulates the components of the information system into editable and reusable service. We want through this article to contribute to the development of a model for interoperability of several different IS, founded on a middleware layer compound of services according to the architecture SOA. The special feature of our model is that it uses an ontological database in the Cloud that will store concepts exchanged among interconnected IS and uses several transformation layers, integration, homogenization and adapting services.