Research On Implementation Methods Of STEP AP216

China's shipbuilding industry has had the basis to become stronger, the government propesed the strategy of digital shipbuilding. To achieve digital shipbuilding, the ship product data must be trending towards integration and standardization in the future.As a basis for implementing and sharing product data, STEP(ISO 10303) is an International Standard for the computer-interpretable representation of product information and for the exchange of product data.This thesis chooses AP216(ship moulded forms) to research, aim to finish the exchange of ship moulded forms data between Tribon_M3 and CATIA by the clear text encoding of the exchange structure.The research in this thesis is focused on the theory system of STEP(STandard for the Exchange of Product Model Data) and its representation methods. The AP216(ship moulded forms) is analyzed integrally, and the article uses wireframe representation to define shape of ship moulded forms, meanwhile, the relationships between AP216 and other shipbuilding application protocols are also researched. All these researches are based on official version of shipbuilding application protocols.The paper uses IGES files which are exported by Tribon_M3 IGES data interface as the source of ship moulded forms data because the Tribon database is unopened. A conversion mechanism was built up by analyzing how to represent the ship moulded forms data in IGES fomat and STEP format.The AP216 application tool is developed in visual studio 2005 by C# programming language. Traditional development methods is discarded and a new methods is proposed that applicaton interpreted model is mapped to C# language instead of C++ classes. In this way, STEP files are generated by windows application. The object is to develop a STEP application plan which has independent intellectual proterty rights.As final result of the paper, step file of an example ship moulded forms is imported into CATIA packge and ST-Developer. The ship lines model is visual and the conversion of ship lines data between CATIA and Tribon_M3 is successful.