The complex engineering project has properties of long time lasting, enormous data amount and wide range of interoperation. To support effectively data management in both different product lifecycle phases and across different systems through web PDM system, ontology based product information model was developed. The model includes concept part for common manage and domain part for specific industries. Concepts and relations were built and introduced. Using ontology improved the machine interoperability. The developed model is validated by the application to the practical web PDM system of enterprise project.