This paper mainly investigates the ability of laser-induced breakdown spectroscopy to discriminate the sedimentary facies of untreated rock samples. Twenty-seven continental and 14 marine sediment samples identified by geologists were used as samples to be analyzed. The line intensity of B, the integral intensity ratio of B/Ga, Sr/Ba, and Fe/Mn lines are used as the discrimination basis for discriminating the deposition phase. Because B, Ga, Sr, and Ba are very low in the rock and are not evenly distributed, a small amount of sample is difficult to distinguish. The content of Fe and Mn is relatively high, so Fe/Mn can distinguish the terrestrial and marine sediment samples well. Overall, the best distinguishing performance was exhibited with respect to other discrimination based on Fe II 259.940 nm/Mn II 259.372 nm. The results show that laser-induced breakdown spectroscopy can quickly and accurately discriminate the sedimentary facies of rock samples at the logging site.