Abstract: To study the underwater explosion shock wave attenuationof the pressure, experiments were carried out with different chargeamount of grain,to obtain the underwater explosion pressure curve and the relationshipbetween the charge volume and the peak pressure. The numerical simulationverifies the experiments. In the case of the same chargeweight, the attenuation of the radial pressure of a grain ofunderwater explosion is obtained. The peak pressure at the explosivecenter is decayed with the increase of the radial distance and thecurve fitting formulas are obtained.