Composite materials have wide application prospects in large equipment in multiple fields， such as aerospace， shipping， and high-speed rail， due to their advantages of lightweight， high strength， and performance designability. However， current commercial software mainly focuses on single-scale functions， such as digital design of composite materials， performance prediction， macroscopic response simulations， and structural optimization. And combined use of multiple software leads to version incompatibility， inconsistent data format and other problems， which makes it difficult to satisfy the current high-end equipment development requirements of on-demand design for the integration of composite material-component-system. Therefore， a cross-system common support platform SWJTU-CAX for design-simulation-optimization software research and development of composite materials and structure was designed and self-developed by combining object-oriented method with modular design idea. In the platform， cross-system development environment Qt and data visualization library VTK were used as basic tools， and data layer， logical processing layer， and presentation layer were used as overall architecture to deal with core difficulties of data management and circulation， functional organization and module expansion， efficient access and visualization of large-scale data in whole process of composite material and structure designs， cross-scale simulation， performance prediction， parallel solving， and optimization design. Besides， code organization and functional testing of SWJTU-CAX were carried out using modular approach and CMake tool， with the help of XML file for management， addition and removal of required functional modules on the platform， and rapid integration and expansion of composite material and structural design-simulation-optimization， as well as other functional modules were implemented. Finally， ceramic composite materials and components were taken as examples， and integrated optimization design and software development of digital modeling， cross-scale performance prediction， response simulation， and structural materials for ceramic composite materials with arbitrary weaving forms were realized on SWJTU-CAX platform， verifying the feasibility of this cross-system platform architecture， data organization， and project management method. It can be seen that the development of SWJTU-CAX platform provides a powerful tool for in-depth exploration of cross-scale failure mechanism of heterogeneous materials and on-demand design of integrated equipment-component-material as well as service safety assessment of equipment composite components， and provides technical ideas and references for domestic industrial software architecture and research and development.