One of the key elements in seismology is determination of site effects and estimating these effects in different regions. The Records of an earthquake is always affected by the earthquake source and directions, the most important part of the record that is effective to strength or weaken of waves is the final part, depending on the type and structure of the layers, affect the waves. Our challenge is that, strengthen and increase the potential vulnerability of ground motion during earthquakes. We can improve our accuracy in calculating of some parameters in seismology by determination of site effects. In most cases, because of high level of strengthening (or weakening) of the effect we can’t ignore it on engineering calculating. One of the important parameters of site effect is the dominant frequency of soil. Site amplification in the Iranian Strong Motion Network, Tabriz stations, was estimated using earthquake 6 events recorded from 2007 to 2012. This seismic network consists of 3 accelerogram stations (TAB4, TAB5 and TAB6) distributed in Tabriz city. A total of 12 three-component waveforms from 6 events were used in this study. Site effects were separated by linear inversion using the reference site (Fathabaad). Site amplification in Tabriz was moderate at low frequencies had a pick value at 2.8 Hz for horizontal component.