The influence of the pulse energy and the pulse repetition frequency are measured. The NdYAG pulse laser which wavelength is 1064 nm is used as the excitation source. The characteristics of laser-induced breakdown spectroscopy(LIBS) of metal element Pb in soil are analyzed. The high resolved and the wide spectral echelle spectrograph and intensity charged coupled device(ICCD) are used as the spectral line separation and detector. The experimental results showed that the spectral line intensity increases linearly with the laser energy from 25 to 105 mJ and increases nonlinearly with laser energy from 105 to 165 mJ. The signal to background ratio increases with the pulse laser energy until the laser ernergy is over 60 mJ, then the signal to background ratio is saturated and unchanged with increment of the pulse energy. In the experiment the maximum of spectral intensity is obtained at the repetition rate of 1 Hz. The minimum relative standard deviation is at 7 Hz.