In architectural design, computer has become a powerful tool, and is deeply relied in areas such as CAD drawing, 3D modeling and datum calculation. However, the potentials of calculation and design assistance of computer in architecture are still remained to be developed. Thus, a case that shows the optimization of plots is presented in this paper to discuss algorithms that realize self-growth model of plots and global optimization among the competitions between each other based on rules and objective functions. The algorithms can be expanded and employed to other fields of architecture, and may provide new architectural methodologies.