Abstract: Four different power samples, sulfanilic acid anhydrous, soluble starch, graphite and calcium carbonate,with different content of carbon were used to determine the influence of element speciation on the properties of laser-induced spectroscopy. The srectral line of CI 247.856 nm was chosen to analye the excitation properties of laser-induced plasma of different carbon speciations. The chemical compositions, molecular binding forces of materials on were used to account for the differences of spectral properties among different forms of carbons. The results show that the excitation energy of carbon in compound with complex structure and greater chemical bond energy requires relatively more energy.