Abstract: The pulse shaper is one of the most important means to achieve constant strain rate loading in split Hopkinson pressure bar (SHPB) test. In order to study the influence of pulse shaper on incident waveform, this paper took copper, brass, aluminum alloy as research objects. The experimental study on the influence of the diameter and thickness of the pulse shaper, the speed and length of the impact rod on the incident waveform was carried out on the 37 mm SHPB equipment. Moreover, combined with numerical simulation and dimensional analysis, the quantitative expressions of dimensional stress and dimensional time at <i<T</i<<sub<1</sub< and <i<T</i<<sub<2</sub< inflection points of incident wave are given. The dimensional stress at <i<T</i<<sub<1</sub< inflection point has linear relationship with dimensional parameters <i<Y/σ</i<<sup<*</sup<, (<i<d/D</i<<sub<b</sub<)<sup<2</sup< and respectively; the dimensional time at <i<T</i<<sub<2</sub< has linear relationship with dimensional parameters <i<h/L</i<<sub<b</sub< and <i<Y/σ</i<<sup<*</sup<.