Abstract: UVs have been used as an important tool in exploring ocean, exploiting resources， military warfares, and other underwater applications. The speed and endurance of AUVs are key factors to evaluate its performance. Since the resistance of AUVs when navigating underwater depends mainly on its geometrical shape and dimension as well as the smooth degree of its surface, it is quite crucial to analyze these elements of AUVs. In this paper， five kinds of AUVs have been designed, including AUTOSUB， HUGIN， REMUS, BLUEFIN1 and BLUEFIN2. Geometric models have been established and researches on their resistance performance have been conducted based on Computational Fluid Dynamics（CFD） analysis. The results obtained from numerical simulation and theoretical formulas have been compared and analyzed to verify the reliability of the simulation process and to determine the optimal model. The characteristics of resistance performance and the optimal design of AUVs have been obtained by comparing AUVs with different horizontal diameters, different aspect ratio of rudders, with or without rudder， with or without faring. It is concluded that AUTOSUB is the optimal type among the five kinds of AUVs， followed by HUGIN, REMUS，BLUEFIN1 and BLUEFIN2， of which AUTOSUB and HUGIN are suitable for high-speed navigation，while REMUS and BLUEFIN are adept for low-speed navigation.