Pounding problem between fixed-based structures due to large earthquakes may cause local damages or lead to the structure’s total collapse. Inadequate gap distance between structures could influence pounding between adjacent structures. Limited studies could be found on pounding analysis of modern systems as based-isolation buildings. In the present paper, we have modeled two adjacent structures, fixed base building and base isolated one in order to assess the effects of near and far properties of earthquakes on their response. Results show that critical impact could occur when mean period (Tm) is close to the natural period of structures. Also, if the highs of adjacent structures are nearer to isolated structures, the effects of near field earthquakes would increase. As a results, with increasing the height of adjacent structure, the amount of affected impact force in near-field motions is amplified 4 times more than far-field ones.