A comparison study between two different approaches for passive vibration attenuation of solar array had been presented. A powerful finite element software “Ansys" was used to perform this study. Finite element models of a cantilever rectangular aluminum plate are created in order to model the satellite solar array. Stiffeners and circular patches (passive masses) are used separately in order to attenuate the vibration of the plate. The output results of the mode shapes and the FRF of the plate are investigated in order to figure out the best and adequate vibration attenuation technique for satellite solar array, the results showed that using stiffeners have a better effect on vibration attenuation more than using circular patches. A further investigation for vibration attenuation using stiffener is conducted to study the effect of changing the aspect ratio of stiffener.