Assuming the internal friction angle of backfill and the displacement are in nonlinear, to adopt the calculation model that was put forward by the author, combined with the in-room model experiment, to calculate and analyze the passive earth pressure acted on the retaining wall in the model of RBT movement. The analysis results show: the calculated values and the test values can agree with each other very well in the three ways of the distribution of earth pressure along the wall height, the values of the passive total force and its action point position. So it is feasible to use the calculation model to calculate the passive earth pressure in the model of RBT movement. Comparatively, when n = 0 the calculated values are the most identical with the test values, when n = 0.25 are worse, when n = 0.5 are the worst. Those may be relative to the sizes effect of the box of model test and the property of the interface between the soil and the plate at the bottom of model box. In addition, with the value of n increasing gradually, the maximum displacement needed to reach Rankine’s passive limit state will be decreased.