The widespread use of rare earth elements has attracted increasing attention. Studies have shown that rare earth elements play an important role in such aspects of the crop as photosynthesis, yield, stress resistance, quality, development and nutrient absorption of crops. Therefore, effective decomposition and rapid determination of rare earth elements in soil can reasonably guide the application of rare earth elements and play an important role in crop growth and soil nutrition. Methods of digestion such as acid digestion, closed acid digestion, microwave acid digestion and alkali melting were studied in this experiment. Microwave digestion-ICP-MS method was adopted which can rapidly and effectively determine rare earth elements in soil. The experiment optimized the digestion conditions including microwave digestion program, dosage of chemical reagent, digestion temperature, and digestion time. The detection limit, precision, accuracy and recovery were tested, which shows the method is effective and feasible. The value was 0.16%～3.39%, 0.27%～5.09% and 93.1%～106.0%.