Abstract: It is inappropriate to calculate the earth pressure for finite soils using the classical Coulomb or Rankine earth pressure theory. A series of laboratory model tests with different widths of backfill are conducted for the passive case of a rigid retaining wall subjected to horizontal translation. The change in lateral earth pressure distribution from the at-rest condition to the passive condition is monitored by using a set of pressure cells. The particle image velocimetry technique is employed to observe the development of a failure zone in the soils. The experiment results show that there is a good agreement between the measured earth pressures and the Coulomb’s solution in the case of infinite soils. However, the passive earth pressures on the moving retaining wall for finite soils are much more than the Coulomb’s solution. With the decrease of the soil width, the limited displacement of the wall under passive state seems to increase, and the passive earth pressures also increase significantly when the heights of the application points of the resultant earth pressure move down gradually. Moreover, with the decrease of the soil width, the heave of the backfill surface increases gradually, the inclination angles of the slip surface increase slightly, and the lateral earth pressures on the fixed boundary also increase gradually.