Based on the traditional laser echo theory, the multitarget laser echo power equation is deduced and simulated and the effects of target laser irradiation area and incident angle on the waveform echo are examined. A multitarget detection experimental platform is built to validate the accuracy of the echo equation, and the effect of circuit overshoot on multiwaveform research is verified through experiments using various receiving circuits, which provide a calculation model for full-waveform decomposition and inversion. Following are the conclusions that can be drawn from the simulation and experiment. The target irradiation area is directly proportional and the laser incidence angle is inversely proportional to the echo peak. For the receiving circuit with voltage overshoot, the experimental results show that when the distance between multiple targets is large, the abscissa difference of the waveform peak in the echo waveform is greater than that of the single waveform pulse width and the average experimental relative error is less than 5%. When the distance between multiple targets is less, the abscissa difference of the waveform peak in the echo waveform is less than that of the single waveform pulse width, the experimental relative error increases, and the average value is more than 10%. After using the new receiving circuit to eliminate the voltage overshoot, the experimental relative error is reduced and the average value is less than 6%. It is demonstrated that improving the receiving circuit’s overshoot or fitting overshoot can improve the accuracy of full-waveform echo decomposition.