Abstarct: Magnetoreological elastomers are a group of smart materials that are made from a combination of polymer and magnetized particles, such as iron powder. These materials react in the presence of a magnetic field, which appears as a change in rheological properties, such as stiffness and damping. The reason of changes is forming the chains of magnetized particles in the presence of a magnetic field. The existence of this feature has led to the use of these materials in the field of mechanical vibration control, which has considered the need to identify the dynamic behavior of these materials. Several factors affect the dynamic response, such as the type and amount of construction materials, environmental conditions, the type and amount of input strain, and more. One of the effective factors is the shape factor. This factor expresses the ratio of the area that is under the mechanical load to the area of the non-load section. In the present research, the aim is to identify the effect of shape factor on the amount of vibrational properties of material in the dynamic state of tension-compression. For this purpose, samples with different shape factor (different diameters) From 0.42 to 0.93 and a combination of silicone polymer, iron powder and silicone oil have been molded and subjected to various dynamic tests. The applied magnetic field is from 0 to 250 mT, the input strain is from 8% to 14% and the input strain rate is from 1Hz to 8 Hz. After performing the desired experiments, the data were filtered using a low-pass filter and their hysteresis diagrams were drawn. The storage and loss modules are calculated for each experiment. According to the results, as the shape factor increases, the amount of compression and tension modulus will increase and the modulus of loss will not change privately.The maximum effect of increasing the shape factor was obtained in compression 39.87% and in tension 52.70%. Another result that can be mentioned is the increase of the storage module and the loss module by increasing the density of the magnetic field. maximum MR effect up to 29.95% for the compression and 21.66% for the tensile storage moduli. Finally, by using the data that obtained from the experiments, a comprehensive model is presented in the state of tension-compression. This model includes the hysteresis section and the nonlinear stiffness and loss section. These components include constants, each is related to the effect of a factor. by using the genetic algorithm of MATLAB software, the recommended values of the proposed dynamic model are optimally obtained. The coefficients of this model are only in terms of magnetic field density and they are independent from strain and strain rate and shape factor. Then, the error value of the presented model with the practical results was calculated, which showed an acceptable value.