Based on the limit equilibrium theory and the Mohr-Coulomb criterion, considering the condition of static equilibrium when the slide wedge was in limit equilibrium, the even load on the arbitrary position behind the retaining wall is researched. The factor exerts an influence to earth pressure. Furthermore, formulas have been derived for the calculation of active earth pressure on cohesive and non-cohesive backfill soils. Numerical example is modeled about active earth pressure on retaining wall, and the results describe that the value of solutions is basically identical with those of theoretical and analytical results. These indicate that the study is valuable for practical applications.