Natural structure can be the basis of new technology development. Underwater floating design iired by nature, always has attracted many marine engineers; for different reasons such as search in the ocean to discover new sources of minerals. The main purpose of this paper is geometrical design of underwater objects and model simulations by the Fluent in 3D mode. Iired by the shape of dolphin, the geometry of underwater floating is generated by the Catia program. The reason of using forms of dolphin’s body its unique features. To analyze the model in the mode of the moving tail, the method of dynamic mesh is used. The floating has been investigated for a fully submerged condition in which the effect of free surface is neglected. According to the Hydrodynamic of dolphin body proper geometry was designed under the deformations of the tail and the body. Four types of designed tails and bodies have been studied and compared. In this research, turbulence models of,?-k ,?-k Standar ,?-k RNG are considered. The results indicated that the drag force values rose with an increase in floating speed form 1 to 3 m/s and decreased with changing the form of floating body. Numerical analysis of the geometry and debate about the implementation of the experimental model will find the fourth model is more appropriate. Because this model is less tolerance of drag force. Continue with iiration from a dolphin's tail in the water, to examine the dynamic mesh model in two-dimensional mode to create the move action. We notice with dynamic mesh when floating in a tail mode, drag force is reduced. Should consider the fact that we are facing a lot of problems for a movement similar to a dolphin swim. In the present work the dolphin's body is considered rigid. Animated tail mode has also been studied. In order to verify the simulation model, the model is compared with an experimental model. Hydrodynamic parameters obtained are compared with the simulation results indicate that compliance is relatively good results. Hence simulated model can be used to optimize and verify the required parameters. This would reduce the cost of testing and cheking the errors of examinations. Keywords: Under Water Floating, Bio Iired, Geometrical Design,Turbulence Model, Dynamic Mesh, Drag Force.