Nowadays different kind of earth and satellite data are used in Earth Gravitational Model (EGM) production and therefore the precision of this model became better and can be used in orthometric height determination. Geoid as an equipotential surface of Earth gravity field and datum of orthometric height system has an important role in civil, exploration and oceanography studies and projects. In this study the accuracy of two Earth gravitational models EGM96 and EGM08 are evaluated in Iran region. Spherical harmonics coefficients of these two Earth gravitational models are used to compute the geoid heights in Iran region. The geodetic coordinate and height of some precise levelling stations in north-east, west and south of Iran were available, therefore the GPS/Levelling method are used to compute the orthometric height of these stations. Root mean square of discrepancies between precise levelling orthometric height differences and modelled orthometric height differences show that the EGM96 is more precise than EGM08 in north-east of Iran and EGM08 is more precise than EGM96 in west and south of Iran.