Prototype experiments were carried out on the explosion-proof performance of the RC blast wall. The mass of TNT detonated in the experiments is 5 kg and 20 kg respectively. The shock wave overpressure was tested in different regions. The above experiments were numerically simulated, and the simulated shock wave overpressure waveforms were compared with that tested and given by CONWEP program. The results show that the numerically simulated waveform is slightly different from the test waveform, but similar to CONWEP waveform. Through dimensional analysis and numerical simulation under different working conditions, the equation for the attenuation rate of the diffraction overpressure behind the blast wall was obtained. According to the corresponding standards, the degree of casualties and the damage degree of the brick concrete building at a certain distance behind the wall can be determined when parameters are set. The above results can provide a reference for the design and construction of the reinforced concrete blast wall.