Abstract: The geogrid-reinforced soil mass is regarded as a marco-homogeneity and anisotropy materials composed of the elasto-plastic soil and visco-elastic geogrids. The soil in the composite mass is of elasto-plastic behavior and its strength obeys the Mohr-Coulomb's criterion of failure while the creep behavior of geogrids is represented by rheological model with a series of a Kevin model and an elastic spring. The equivalent stress calculation of geogrids is established on the basis of fundamental of mechanics of composite material. The results considering rheology are compared with results gained by method with non-rheology.