Abstract: This experiment with DTPA as extracted,Ultrasonic extraction is established-inductively coupled plasma mass spectrometry（ICP-MS） in the determination of soil effective state of Fe,Mn,Cu and Zn. Experiment investigates the factors such as ultrasonic extraction time, measurement conditions, and has carried on the contrast research to eliminate matrix interference. Under the condition of the optimization of the ICP-MS,the results shows that effective state of Fe Mn Cu and Zn have good linearity in the concentrations of 1~200 μg/L. and the detection limits of the method are 45.6 μg/L、0.90 μg/L、0.32 μg/L、0.44 μg/L, the relative standard deviation less than 5%（n=6）. The precision and accuracy of the method were verified by analyaing national standard reference materials, The relative error less than 5%（n=6）, there was no significant differentce between this method and national standard method（NY/T890-2004） by test and the results were consistent with the national standard method. This method has characteristics of convenient low detection limit high accuracy and good precision, which can be applied to determin with available forms of effective state Fe Mn Cu and Zn in large batches agricultural pollution soil.

Key words: soil, ultrasonic extraction, inductively coupled plasma mass spectrometry （icp-ms）, effective state, mineral elements