Developing the seafloor observatory network(SONet) is very significant for the human to explore the ocean resources. The information system of seafloor observatory network provides a platform for scientists to research the seafloor activities, which is a kind of open and complex system referring to diverse engineering and disciplines. The data acquiring, storing and management of the observatory instruments are the major parts of information integration. A prototype system based on the SOA(Service-oriented Architecture) is designed to manage information and knowledge in SONet. The SOA architecture, interface and device encoding mechanism are presented. Benefit from this, construction and application of the system can provide a uniform information and knowledge platform in the ocean field.