Abstract: A method for the simultaneous determination of 9 toxic and harmful elements, including As, Cd, Co, Cr, Ni, Pb, Sb, Tl and V in organic fertilizer by inductively coupled plasma mass spectrometry (ICP-MS) with microwave digestion was proposed. The organic fertilizer sample (0.10 g) was placed into a polytetrafluoroethylene microwave digestion tank, and 2.5 mL of hydrochloric acid, 7.5 mL of nitric acid and 2.0 mL of hydrofluoric acid were used as the mixed acid for microwave digestion. After digestion finished, the acid was driven at 140 ℃. Then 1.0 mL of 50% (volume fraction) nitric acid solution was added, and the volume was made up to 50 mL with water. The mixed solution was shaken well and filtered, and the filtrate was taken to be determined with adding the mixed internal standard solution online. It was shown that the linear ranges of the standard curves for 9 elements were 2-100 μg·L^-1, with detection limits (3s) of method in the range of 0.59-66.75 μg·kg^-1. Test for recovery was made on the typical organic fertilizer sample according to the standard addition method, and RSDs (n=7) of the determined values for 9 elements were in the range of 2.0%-3.5%, with recoveries ranged from 81.5% to 112%.