Abstract: The defects of metal components change greatly for various reasons and there may be multiple defects in damage location. A 2D model of an axisymmetric probe coil is developed to achieve the reliability of eddy current testing(ECT). The model of ECT is applied to the simulation of two defects in the presence of a pipe line. The variations of the amplitude and phase of ECT signal with the change of geometric state of two defects are computed in this paper. The stimulation results show multiple defects on the eddy current signal are different from the single defect. There are different deviations of composite signal with the exciting frequency change. The different geometric state of defects near damages location will also have impacts on composite signal of those defects which have less depth. This can cause inappropriate damage evaluation, but it can get a careful analysis through the difference of the amplitude for composite signal.