The structure and composition of plant communities may be mainly affected by fire and grazing، especially in arid and semiarid rangelands. This study aimed to investigate the role of fire and grazing on vegetation dynamic and soil seed bank characteristics in Semi-Steppe rangelands of Central Zagros. First، a Bayesian belief network () model was built to predict fire occurrence in Isfahan province. The environmental and management data from 250 fire sites and 250 random sites with ‘no fire’ experience in Isfahan province were used to construct and evaluate the model. Twelve biotic، abiotic and anthropogenic variables were used to build a cause and effect model. The sensitivity analysis revealed that land cover، mean annual rainfall، mean annual temperature، elevation and livestock density were the most important influencing factor on fire occurrence. The AUC value of the model was 0.986، indicating its excellent performance to predict fire occurrence. The effects of fire products on seed germination status of seven dominant range plant species were evaluated in the next step of this study. The effects of six treatments including 3 heat levels (60°C، 80°C and 120°C)، 1 of aerosol smoke (10 min)، 1 of ash (10 g/l)، and 1 of control on seed germination of these species were compared. The results indicated that fire products had different effects on the seed germination of the species. The germination percentage of Astragalus adscendens increased following a 60°C heat treatment in comparison with control. The germination of Astragalus verus ، Bromus tectorum ، Bromus tomentellus and Phlomis olivieri ، were increased significantly using smoke treatment (P 0.0001). While the seed germination of B. tomentellus and B. tectorum was promoted by ash treatment، in addition، smoke treatment shortened the overall germination time of B . tectorum . In the next step، the role of fire and grazing on vegetation dynamic and soil seed bank were studied. A stratified random sampling method was used to collect the vegetation data from 30 sites with one and five years after the last fire event with light and heavy grazing history. Soil seed bank were studied in 12 sites، randomly selected from the 30 sites. According to the results، the richness، diversity and contribution of palatable plant species in vegetation composition and soil seed bank were increased by light grazing post fire، but beta diversity was decreased in the sites with different levels of grazing impact. Heavy grazing post fire resulted to decrease litter and vegetation cover percentage and increase the bare soil size in the area. Soil seed bank was decreased significantly due to fire events. Fire also modified the vegetation composition of rangelands، in which the Hemicryptophytes and Therophytes were decreased and increased respectively. The results showed that the fire and grazing did not have significant effects on the functional diversity in vegetation cover and the soil seed banks of deeper soil layers. The similarity between soil seed bank and standing vegetation was low in the study area but this similarity was increased in the sites with fire experience. Overall، it can be concluded that the proper grazing management post uncontrolled fire event has a suitable solution in the semi-steppe rangelands of Central Zagros. Keywords : Isfahan, Chaharmahal and Bakhtiari, Diversity index, Bayesian belief network, Fire products, Modeling