Main principles about UUVs design and missions are described in the paper. The hull shape of UUV should be solved firstly in UUV overall projecting and directly impacts to energy consumption, mobility, deep range, hydraulic resistance and navigation. The layout of three main shapes of UUVs is given in this paper and introduced total layouts figures. The main form of UUV is torpedo hull type, due to high pressure endurance and low drag coefficient. New flat streamline form provides better vertical plane and anti-jamming ability. Other anomalous shapes are designed for performing a specific task and the hydraulic resistance performance is not sufficient. UUV are implemented in many common missions. These missions can be divided in three groups, such as research, commercial and military. The common missions of UUVs are given in the paper. Considering the analysis of design, shape and missions of UUV and the tendency around the world, the Authors according to the prior direction of states science development – Innovative materials and technologies, start the research on UUV best design and shape, adapting it at first for ship underwater hull inspections.