This paper studies the variation of soil density and earth pressure in a soil mass due to the vibratory compaction along a strip on the surface of the cohesionless backfill. Experiments were conducted in a non-yielding model retaining wall facility and dry Ottawa sand was used as fill material. Based on the test results, it is found that surface settlement increased with the increasing number of passage of the compactor. The relationship between the surface settlement and the number of passes could be properly described by the hyperbolic model. The contours of Δσ v after the first passage of the compactor were analogous to a series of concentric circles. As the number of passes increased to 8, the depth of the compaction-induced zone increased with increasing energy input. After the first passage of the compactor, the contours of Δσ h formed two regions of stress concentration below the surface. As the number of passage increased to 8, the two high-stress regions merged. The mechanism of soils after the first passage of the compactor could be properly explained by local-shear bearing capacity failure mode. The mechanism of soils after 8 passes of the compactor could be simulated by a single pile driven into a cohesionless soil.