This paper proposes a optimal design method of base-isolation device and frame member in a reinforced concrete building. The proposed algorithm called DCMOGA( Distributed Cooperation model of MOGA(Multi Objective Genetic Algorithm) and SGA (Standard Genetic Algorithm) ) and conventional multi objective optimization are applied to design two buildings. Finally, a comparison was made among design solutions. Comparing to the conventional multi objective optimization methods , the proposed model found the widespread Pareto solutions. Consequently, the effectiveness of the proposed model was demonstrated.