Explosion containment vessels are widely used in many fields. Here, the detonation impact load of explosives in a cylindrical closed explosion containment vessel partially filled with sandy soil was studied. A three-dimensional numerical model of the explosion containment vessel was established by using finite element code ls-dyna. To calibrate this numerical model, we carried out an explosion loading experiment of the explosion containment vessel. Then, the experimental data and the numerical simulation results were compared, and a good agreement between them was obtained. The calibrated numerical model was used to investigate the explosive impact load generated by explosives in a cylindrical explosion containment vessel. The results reveal the attenuation law of shock wave overpressure and the distribution characteristics of the maximum peak overpressure of the shock wave on the inner wall of the cylindrical explosion containment vessel.