Vibro-Impact dampers are of much interest in recent years due to their capability in rapid reduction of dynamic structural responses under transient vibrations such as earthquakes. In the present work, systematic search of VI parameters is concerned via an optimization problem formulation to improve its performance under seismic excitation of building frames. In this regard, VI parameters including impact distance, mass and stiffness ratio are taken as design variables in each case of topological variation of VI-setup among the moment-frame stories. Particle swarm optimization is thus utilized to solve such a for continuous search problem as a recent successive meta-heuristic algorithm in similar engineering fields. A number of low- and medium-rise building frame examples are then treated using numerical time-history analyses under a variety of destructive earthquakes. As a result of the present study with optimized VI parameters, the upper stories of building frames are preferred for setting up the impact dampers to achieve best structural response while installing such equipment at the lowest story can highly decrease the number of successive impacts and consequent performance of the proposed seismic control.