Abstract: This paper presents the dynamic properties of a model for a five-story, 1/5-scaled low-ductile infilled reinforced concrete frame by applying a dynamic test. The low-ductile structure was designed in terms of poor seismic fortification level, insufficient seismic fortification measures, and long service ages. The masonry infilled walls would separate from major structure members or cracked under a low intensity excitation, so that the white noise used for the specimen had a low amplitude and short duration. The system identification of the specimen was extracted from floor accelerations under white noise excitations by the eigensystem realization algorithm method and nature excitation technique. The acceleration response of each mode was analyzed, which extracted by a wavelet transform. It is shown that the eigensystem realization algorithm method is effective for a lower strength vibration. A high modal vibration is easy to occur for existing RC frame.