Abstract: Sample of soil was digested with a mixed acid of HCl and HNO3 (3+1) in a microwave digestor , and the content of molybdenum in the sample solution was determined by GF-AAS. Ammonium nitrate was used as matrix modifier. The temperatures of 2-step ashing were 800 ℃ and 1 600 ℃ and the atomization temperature was 2 900 ℃. Linear relationship between values of absorbance and mass concentration of molybdenum was obtained in the range within 40 μg·L-1, with detection limit (3s/k) of 0.69 μg·L-1. Three CRM′s of soil were analyzed by the proposed method, giving results in consistency with the certified values and values of RSD′s (n=5) obtained were in the range of 2.6%-5.8%.