It is necessary to construct equipment catalog in ship outfitting design and offshore plant design. The three-dimensional CAD data of equipment take on different level-of-detail depending on the purpose. Equipment suppliers provide CAD data with high complexity while ship designers need CAD data with low complexity. Therefore, it is necessary to simplify CAD data. However, it takes much time to simplify them manually. To resolve the issue, a system for automatically simplifying the 3D CAD data of equipment was developed. This paper presents the architecture of the system and the implementation details. In addition, experiment result using the prototype system is explained.