Abstract: In order to research the reverberation generated by underwater explosion, an advanced three-dimensional short-range bistatic reverberation average strength model is established based on the ray theory, using the geometric character of ellipse, and formula for computing reverberation strength is deduced. The effects of explosion depth and pulse width on reverberation are analyzed. The calculation results are compared with the experiment data, which indicates that the effects of explosion depth on reverberation are relatively small, reverberation strength increases by the pulse width increases.