In architectural design, computer aided design tools have an important impact on design process, but still early design stage and sustainable design are problematic issues. During sustainable architectural design process, the designer needs to comply with some regulations, which requires calculations and comparisons. Green building certification systems are developed to assist designers during this complicated process, but for an efficient sustainable design for different regions, environmental information and local building codes must be considered with green building certification system criteria. In this paper, LEED and BREEAM certification systems are going to be considered as being the most representative building environment assessment schemes that are in use. As there are conflicting criteria's according to LEED and BREAM sustainable site parameters, local building codes and environmental conditions; an efficient decision support system can be developed by using multi-objective genetic algorithm. This paper presents an effective site-use multi-objective optimization model that use pareto genetic algorithm to determine the most efficient sustainable site layout design for social housing, which could assist designers in the early stage of design process.