Visual programming language which represents the Grasshopper of Rhino is being developed as the core element technology by being connected the architectureal design. For its application in the case of the free-form architectureal external panel, the problems like extraction of point coordinate for the construction and optimization of the panel size according to the construction material are coming to the fore and the solutions for these problems are necessary. To solve these problems, this study has established the genetic algorithm based optimization process of free-form architecture external panel for the improvement of the construction quality and to control amount of data of external panel and has proposed the utilization method, The results deducted from this study are as follows: First, optimization method for the architectureal external panel can be early just from the early design stage and can create automatically optimized design alternatives by using reasonably the various conditions of the genetic algorithm. Second, the optimization alternatives can be created according to the evolved calculation generation instead of inputting complex parameters for the optimization of the free-form architectureal panel. Third, real time coping is possible in the numerous design feedback process and thus task efficiency can be enhanced on the architectureal process level and the digital data can be extracted necessary from the early design stage and can be utilized directly in the free-form architectureal construction. Also, it is judged that new architecture environment shall be provided in the main agent-specific cooperation.