The need for sustainable energy is necessary because of the increasing consumption of energy in the world. Wind turbine farms and offshore wind turbines are one of the renewable energy resources. The need for a suitable, efficient, and resilient foundation requisite the use of these types of turbines. One of the newest and most efficient types of marine foundations is the suction caisson, which installs in the same way as an inverted cylindrical bucket by pumping water from the seabed. In this study, the effect of geometry change in the tensile capacity of the buckets studied by finite element simulation using Abaqus. For this purpose, first, an axisymmetric model was simulated and then the obtained results compared. The results show that with the increasing displacement rate, the resistance to the pull of the caisson is sharply increased. Unlike that, with the reduction of the pull-out rate, the resistance decreases significantly. Then, in order to evaluate different geometries, the simulation transformed from two-dimensional to three-dimensional model with the same geometry (cylindrical). Next, the results of the simulation of the 3D model were verified with the two-dimensional models. Then, by applying geometric changes in the three-dimensional model, the capability of the suction buckets with the triangle, pentagonal, hexagonal and octagonal geometries are investigated. The results show that the resistance to pull-out of the cylinder is better than the other geometries and any change in the cylindrical geometry is not reasonable. Keywords : Suction bucket foundation, Finite element method, Tensile capacity, Caisson