In order to solve inconvenience of crossing platform model data extrapolation in engineering design software, the model and data format of common design software Plant Design Management system(PDMS) and CREO were studied, and the data composition of rvm file in PDMS platform and stp file in CREO platform were analyzed, Besides, the MongoDB database was established. And in order to contain complete model information, the 3D engineering data standard and the 3D engineering data format compatible with multiple platforms were designed, which is defined as AOS format, Then, a representation method for the model object class and the connection relationship between objects were designed, which can fully describe the 3D design model information of the project. Meanwhile, develop a data standard conversion interface to complete the bidirectional conversion of PDMS platform data to CREO and the inverse conversion. Through deployment in actual projects, it has been demonstrated that the established 3D engineering data standards and conversion interface models have high conversion efficiency, and the information push is accurate, data packet loss is low, which can effectively solve the problem of crossing platform transmission barriers for 3D models.