Abstract: The method for determining harmful elements of copper, lead, iron, manganese, sulfur and phosphorus in motor gasoline by inductively coupled plasma mass spectrometry (ICP-MS) was studied. The samples were measured directly after diluted properly. The dynamic reaction pool technology （DRC）was used to eliminate the interference of polyatomic ion. By discussing the effect of the reaction gas flow of methane and oxygen on the back ground equivalent concentration (BEC), the optimum reaction gas flow was ascertained. The detection limits for copper, lead, iron, manganese, sulfur and phosphorus are 0.009, 0.024, 0.024, 0.072, 5.138, 0.557 μg/L, respectively. Precision and accuracy of the method are good enough to meet the requirements of gasoline detection.