Abstract: Low sampling frequency and echo broadening are the main reasons for low peak detection accuracy in digital pulsed laser ranging. The traditional inverse distance weighted interpolation algorithm (IDW) for peak detection can only solve the problem of low sampling frequency. Aim at the problem, an improved inverse distance weighted interpolation algorithm(ⅡDW) was proposed. The sampling peak value is firstly located, then sampling spots within the researching radius of the rising edge and falling edge were assigned with different weight according to the different distance to the peak value separately, finally the peak time was corrected by weighted average. This algorithm reduces peak detection errors caused by restriction of sampling frequency and echo broadening effectively and improves the detection precision of digital pulsed laser ranging.