The laser induced breakdown spectrometer (LIBS) is used to quantitatively determine the rare earth elements in the soil samples, and the certified reference materials for the chemical composition of soils is used as a study objects. The laser output energy , gate delay time, spot diameter, laser repetition rate, flow of protective gas (He) and other instrument operating conditions effect on the measurement results, the affection of working parameters on the measurement results is evaluated by the normalization method (measured value compared with the certified value), which is found that the laser output energy and gate delay time have great influence on the measurement results, and the best working conditions of the instrument are selected: 1.6 mJ of the laser output energy, 0.1 μs of the gate delay time, 70 μm of the spot diameter, 20 Hz of the laser repetition rate, 0.3 L/min of the protective gas. Based on this working parameter, 10 certified reference materials for the chemical composition of soils are selected, and multivariate calibration curves are used. The R values were all greater than 0.99, the calibration curve has a good linear relationship, therefore this method can accurately determine the rare earth elements in soil samples.