The Alborz region is an arcuate fold-and-thrust mountain belt in the north of Iran. It is ~100 km wide, ~1000 km long, and curves along the southern margin of the Caspian Sea. The structural trend of the Alborz changes fromN1100 E in the western Alborz to N800 E in the eastern Alborz, and a marked hinge occurs near longitude 52.50 E. Evaluation of stress area in the region earlier study conducted by researchers has been working with us in this whole area into smaller sub-areas, turning special attention to host events in seismic zones, we have focused on other things it has not been paid. We investigate the spatial variations of seismicity along these zones in an attempt to investigate fault complexity along strike, quantified by the Gutenberg-Richter b-value and the fractal (correlation) dimension of earthquake epicenters, by using the correlation integral method, from magnitude distribution (b value) by maximum likelihood method. The investigation covers instrumentally recorded earthquakes of magnitude M > 4.5 occurring between 1900 and 2011. We find systematic spatial variations which may be related to structural or mechanical variability along strike. The correlation dimension (1.57<D<2.12) and b (0.5<b<1.1) value, respectively computed from the earthquake epicenter and magnitude distributions show significant temporal and spatial variation related with seismo tectonic feature of fault zones. Beside some parameters of fault zones were determined to have bifractal properties. Our results show that the tectonic stress in the Alborz region is changed between 2.1 to 15 MPa.