Abstract: Based on Arbitrary Lagrange-Euler (ALE) algorithm, the paper utilizes finite element software AutoDyn to analyze the propagation of the explosion shock wave when it meets the retaining wall after the TNT is detonated on the ground. Over-pressure distributions on different directions were predicted when TNT was detonated in the free air, on the rigid ground and on the sand ground. The distributions of the over-pressure and impulse along the height of the retaining wall were investigated when the shock wave met the wall. The distributions of the max peak pressure and impulse behind the retaining wall were also studied when the shock wave diffracted over retaining wall. The result shows that different detonation environment leads to different pressure distribution. The reflected pressure is about two times higher than the incident pressure when the shock wave is reflected from the concrete wall, and the max pressure and impulse occur at the base of the wall when the scaled distance is small. The shock waves converge when the shock diffracts over the retaining wall, and the pressure will be enhanced because of the wave impact.