A new method of by time-delay superimposition was developed which could effectively improve the detecting signal-noise-rate of laser radar on the basis of spectral characteristic analysis.A larger number of laser radar echo signal was obtain by experiment.And the practicability of using time-delay superimposition to improve the detecting signal-noise-rate of laser radar was discussed on the basis of it.The results show that on the condition of 50 MHz system bandwidth and 30 ns impulse width of echo wave,time-delay superimposition could improve the detecting SNR of Laser radar more than 40%.Also the optimally time also was existence.