Abstract: Amplitude characteristics of vertical ground surface vibration caused by explosion seism are studied by using the experimental method. The explosive packages charged with 2 kg TNT, laid on the ground surface, above the ground and under the ground respectively, are ignited and the vertical ground velocities generated by their explosion seism are measured at different places from the explosion center. Their analyses show that both the maximum vertical ground accelerations and the maximum velocities follow the relations with negative power of the distance, and there is much longer duration for the velocity than for the acceleration.