Abstract: The performance of a magnetic particle testing system is affected by many factors, such as the waveform of the electric current (its peak value) and the test blocks in use. This article describes how to perform a series of tests to find the influences of current waveforms (peak effect)and testing on magnetic particle testing system performance. In the past, not enough attention was paid to these factors. The authors try to analyze the mechanism of magnetic particle inspection in order to help people to be able to better control magnetic particle testing system performance.