: Naien Zone is located between and , which is one of low seismicity region ( Few records of historical and 20 th century earthquakes), in Centeral Iran Seismotectonic Province . Tectonic and seismotectonic evidences and so active fault effects on quaternary deposits mention to a capable seismicity region, maybe this feature ( low seismicity) refer to the long return period earthquakes or different sorts of releasing energy. According to the text, seismicity investigation risk hazard assessment on this region even with seismic gap is inevitable. This research is going to do the seismicity investigation and probabilistic seismic hazard analysis on Naien Zone . The research has been conducted by two methods. First method, uses Tabas seismicity parameters ( In order to similar seismicity history), the second one synthetic catalog prepration base on Monte Carlo Simulation method( Using the real and limited earthquake records of Naien Zone , and those statistic parameters). In both methods, peak groud acceleration has been calculated for different ranges of magnitude and attenuation relationships. So the hazard curve related to each seismic source, totall hazard curve, return period figure and probability of occurrence for the specific period time related to all seismic sourses base on annual probability of exccdence and hypothetical accelerations (0/05g, 0/10g, ….… , 0/60g, 0/65g) has been calculated and drawn.
