It is a relatively new task to apply the laser-induced breakdown spectrosopy(LIBS) to plant samples. To apply LIBS technique in the field related to foodstuff safety, we have done primary experiments using three kinds of fruit samples prepared by vacuum freeze-dried technique using the technique of discriminated LIBS spectra. The relative contents of six trace elements Ca, Na, K, Fe, Al and Mg in the samples were analyzed. By comparison we found that in apple samples the relative content of Na is the highest and the relative content of Ca is the lowest, and the contents of K, Fe, Mn, Mg are different for different fruit samples. Experiment results showed that LIBS technique is a valid means for measuring and comparing the content of trace elements in plant samples.