In order to generate STEP-NC data model in keeping with the ISO14649 protocol, extend the STEP model to the field of the CNC, the paper analyzes STEP standard and its file structure, develops the display software which can be read and display the STEP format file based on open source Open CASCADE geometric kernel by using the Visual Studio 2008 software development environment, designs one instance by using Pro/E software, and stored as a STEP format file in Pro/E environment, and then, using the software developed to read and display the STEP file. The results of this study improve the product data exchange and integration capabilities, lay a good foundation for generating the STEP-NC format file in the future, extracting the file STEP-NC machining information, and achieving CAD / CAM / CAPP integration system.