This book systematically studies the key technology of improving the design of the digital ship design, subdivision design and structure design of the main hull. In the absence of the parent type case, it puts forward rapid design method based on the approach of energy optimization, top-down parametric non-manifold subdivision design method and rapid optimization method of hull structure based on knowledge driven. Each part gives an example of engineering application, in order to confirm the feasibility and superiority of the proposed method. This book can be read by people in the field of naval architecture, and also provides reference for the relevant professional undergraduate students, graduate students and university teachers.