The erythrocytes play an important role in delivering oxygen and carbon dioxide in the human body. They are generally believed to be highly deformable and are able to squeeze through small capillaries. The elastic rigidity of the cell is associated to the change in free energy caused by both the stretch and the bending of the erythrocyte membrane. If the curvature of a shell is changed by deformation, the bending stiffness must be considered. However, researchers usually focus on the stretch of the cell membrane while analyzing the experimental data. In this article, mechanical models were proposed to study the erythrocytes deformation during optical tweezers stretching and micropipette aspiration. The effect of membrane bending stiffness on the cells deformability was concluded using finite element modeling and simulation.