This paper focuses on developing a genetic algorithm (GA) to build a computer aided architecture design tool. Some important housing design factors such as the spatial massing, the individual space allocation etc. are utilized by the genetic algorithm for designing the better even “optimal” architecture design plan. Thus, the computer aided architecture design system can really reach the objective of aiding designer while designing a specific architecture design plan. The main contents of this research include four aspects. The first one is to recollect the fine housing case studies in the real world of their spatial allocation existing in architecture design plan. The second one is to study the feasibility of applying GA technique to computer aided architecture design. The third one is to build an appropriate system for the allocation of an architectural bubble diagrams. And finally, the fourth aspect of this research is to adopt Evolver program plugged in Microsoft Excel built in the computer aided architecture design system. Concluded from the four aspects mentioned above, the main contribution of this research is the development of a methodology (i.e., GA technique) for aiding architecture designer to design an architecture design plan more efficiently and effectively.