One of the most important phenomena in an earthquake, is the phenomenon of resonance. The main objective of this research is to provide a method for determining the Frequency of the Fundamental Mode (FFM) structure in order to avoid this phenomenon. The research, which was conducted in Tehran, recorded Ambient Vibration data (Microtremor) caused by Metro Tarasht Station, Human activities, Urban traffic and etc. are recorded. We used Horizontal to Vertical spectral ratio (H/V) method and Dynamic analysis of structures can be extracted FFM of structures to examine the possibility of resonance. This method is very good because it is cheapness and easy application. In this research, for 4 buildings around Tarasht Tehran subway with Digital seismometers CME on two consecutive days using above method, the fundamental mode frequency of structures has gained. As a result, the estimated frequency of this method is more accurate and the amount of error is maximum 0.2 (Hz).