Taiwan is located in the seismic zone; therefore, it is very important to strengthen the structure of the buildings. Unreinforced infill bricks are frequently used for partion walls and exterior walls in old buildings in Taiwan. But there is an issue that is the seismic behaviors and design formulas are not well specified in the existing Taiwan Buildings Code. The purpose of this paper is to provide the reasonable simulate methods and to establish the fundamental information of brick walls. The main content of this research is to discuss the effects of wall on RC structures by using ETABS V8.48 and the method of ”the Seismic Capacity Assessment for RC building”.