The content of Sulfur and phosphorus in chrome steel samples were quantitatively analyzed by laser induced breakdown spectroscopy. The plasma was obtained by Nd∶YAG(1 064 nm)pulse laser in air atmosphere. The spectrum range from 200 to 800 nm was detected by Echelle spectrograph and EMCCD detector. The effects of detection delay time and laser pulse energy on the spectral intensity were investigated. Under optimal conditions, sulfur and phosphorus in the three chrome steel samples were quantitatively analyzed using the internal standard method. The experimental results showed that the maximum relative standard deviation was 2.6%, and the relative errors were -8.3%~12.5%. The content of sulfur in the three chrome steel samples respectively were 0.011%, 0.0079% and 0.0048%, and phosphorus were 0.015%, 0.014% and 0.009%. LIBS technology is an effective tool for spectral analysis and expected to achieve real time, online and rapid detection for steel samples.