Abstract: The microwave digestion and ICP-MS was employed for sample pretreatment and elements determination in the marine sediment during the intercomparision exercise organized by IAEA-EL. For evaluating the uncertainty,the factors of sample weighing, digestion procedures, the volume type, the dilution of standard solution, curve fitting and the measurement repeatability was estimated, and the result show that the uncertainty derived from sample digestion procedure was the major factor to affect the accuracy in the trace elements analysis. According to the final evaluation report from IAEA-EL,the results were acceptable based on the Z-score evaluation method,except the elements that Z-score values were not calculated.