Nowadays with significant increase in population and urban areas, development of infrastructures and roads as a basic issue for sustainable development is accelerating intensively. In fact, construction of retaining walls as an inseparable part of roads and bridges is increasing significantly. Comprehensive understanding of active and passive earth pressure plays major role in safe and economic designing of retaining walls. It has been tried to make a numerical model a cantilever retaining wall using PLAXIS software, which is more complicated and precise than classical methods. The results showed that distribution and magnitude of earth pressure as well as the point of application of resultant force differs with that of classical methods. This deviation is attributed to the flexibility of the retaining wall system and combinational mode of wall’s movement. Moreover, effect of cohesion on earth pressure in both active and passive conditions were examined and compared.