In the experiments, laser induced breakdown spectra produced by infrared radiation of NdYAG nanosecond laser, are measured by fiber optic spectrometer for navel orange. The characteristic spectral line of PbI 405.78 nm is selected as the analysis of line. By measuring the intensities of the characteristic spectral line with different Pb concentrations. According to relation between the spectral line intensity and concentration the calibration curves are established. The experimental results show that the spectral line intensity increases linearly with the concentration of Pb under the condition of low concentration,and increases nonlinearly with the concentration of Pb under the condition of high concentration in Gannan navel oranges, of which minimal fitting degree (R2) are 0.95 and 0.98, respectively. The experimental results also show that, LIBS can quickly analyse the relative content of the heavy metal element in the fruit sample, and can be applied in the field related to foodstuff safety.