Abstract: A water tank was designed to explore bubble pulses of underwater explosion. In the designed water tank, small-scale underwater explosion tests were conducted for different TNT-equivalent PETN charges of 0.125, 1.000, 3.370, 8.000 g. After explosion of the PETN charge, bubble pulses were obtained by a high-speed camera system. Variation of the bubble diameter, expanding and contracting velocities, and expanding and contracting accelerations with time was achieved in the bubble pulse process under the given experimental conditions. The data of the bubble diameter and pulse period were analyzed. These data for bubble pulse obtained in this research accord approximately with a similarity rule.