Agricultural products have complex matrix prohibiting the development of LIBS (laser induced breakdown spectroscopy) in detecting its composition, especially tracing toxic heavy metals. The work was aiming at improving the sensitivity and accuracy of LIBS in predicting heavy metals in farm products. Fresh pork was chosen and dipped in Pb solution for making polluted samples. The samples were dried, ground to powder and pressed to pellets to remove the effect of water. The LIBS spectra of fresh and dried pork were collected at the same experimental conditions. The results demonstrated that the intensity of Pb was similar and obscure in fresh samples, but quite strong and clear in dried ones. The linear calibration curve between real content of Pb and intensity of Pb Ⅰ 405.78 showed that the correlation coefficient was poor in fresh pork and good in dried samples and the limit of detection of dried samples is 5.13 mg·kg-1. This experiment testified that the sensitivity and accuracy could be improved after the fresh samples were pretreated by simple physical methods, and it is potential in predicting heavy metals in farm products by LIBS. And this method can also be applied to other meat of detection by LIBS.