Abstract: In order to research on CATIA V6 ship duct design and related data, combined with a practical engineering background, a three-dimensional design method for the CATIA V6 ventilation system is exhibited, and the catalog composition of duct fittings and duct lofting process are presented. Meanwhile, revolving around the system design modules, the module processing objects and data storage location are analyzed in order to determine the object of study. And on this basis, the definition and specific content of the engineering technological tables are illustrated in detail; specifically, the contents are extended. Moreover, in light of the three-dimensional model, further research into the underlying data structure of ventilation ducts is implemented. The relationships between the major technological tables are shown. The results of the study are not only beneficial for designers to grasp design technology, but also essential for software developers to secure theoretical guidance and technical support.