Abstract: The method for simultaneous determination of 12 heavy metals including Mo, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd and Pb in Mytilus edulis was established by ICP-MS with quadrupole collision cell technology, and using microwave digestion technique.The application of kinetic energy discrimination (KED) could eliminate the interference of polyatomic ions effectively.⁴⁵Sc, ⁸⁹Y, ¹¹⁵In and ²⁰⁹Bi as internal standard elements were also used to compensate matrix effect and signal drift, and the optimized conditions and technical procedures of the determination were established.The method of KED-ICP-MS for determination of heavy metals in Mytilus edulis was satisfactory, the relative standard deviations were between 0.66% and 3.91%, the recovery rate of the method was in the range of 86.2%~102.0%, and the detection limit ranged from 0.001×10^-9 to 0.118×10^-9.The results indicated that the method was convent, sensitivity, accurate and precision.It was suitable for determination of these elements in marine organisms, and also provided scientific foundation for safety assessment and quality control.