At the building planning and design stage, level of seismic resistance in building planning typically correlates negatively with project cost effectiveness as the two objectives of seismic resistance and cost control are often in conflict. As architects must regularly address this trade-off between degree of seismic safely and project cost, may be indecisive when planning building. It is an issue that deserves to be explored further. This paper developed an optimal planning mode that used fuzzy theory to determine architect preference functions in terms of seismic resistance and cost effectiveness, and then combined such with an indifference curve to deduce planning weights. The Data Envelopment Analysis (DEA) method was also employed to determine the efficient frontier of the school buildings to serve as the basis for architects to apply this model in their own projects. A total of 326 school buildings in Taichung City in an empirical study designed to elaborate the developed research method. Optimal planning model for school buildings was achieved to provide a paragon for architects to plan future school buildings.