Abstarct: In recent years, because of population increase in urban areas and problems like ground structures density and optimal use of it, traffic,air pollution and … the use of underground spaces has turned in to a solution to this problems. Meanwhile, the use of metro tunnels has been widespread to improve urban transportation. Today, due to remarkable development of technology in tunneling and their advanteges, the use of all types of mechanized tunneling machines specially EPB is increased. Ground settlement is one of the most important challenges of tunnel excavation that because of ground structures in urban areas, weak ground and shallowness of structure is very important. Therefore, it is essential to estimate the ground settlement and it is examined by many scholars. In this research numerical modeling by finite difference method is used and tried to be as much as possible similar to actual tunnel costruction. One of the most basic stages of numerical analysis in geotechnical projects is choosing the appropriate constitutive model. This issue is considered as the subject of this research. In this research, comparison of the value of ground settlement and moitoring results is done by considering elastic, mohr-coulomb and strain hardening soil models, then the best constitutive model for describing the ground settlement behavior in metro Qom line-A is presented. The results of numerical analysis show that the most Estimated settlement is related to hardening siol model and the less is related to elastic model. The most matching with monitoring results has been related to hardening soil model.the results show that the use of advanced constitutive models that apply multiple factors to estimating settlement, imprives the results to an acceptable level. The results of parametric analysis showed that by increasing in values of elastic modulus, cohesion, friction and insitu stresses ratio, the value of ground settlement decreases. Also, the most effect on settlement value has been related to insitu stresses ratio, friction, elastic modulus and cohesion, respectively.