Abstract: In order to enhance the testing ability of pulsed magnetic flux leakage(PMFL) for shallow defects, the method of second difference for dealing with testing signals was put forward, which separated the eddy current components, namely second differential signals, caused by the damping of eddy current effect from the signals in pulsed magnetic flux leakage. From second differential signals, a new characteristic quantity of the depth of shallow defects—peak time Pt was extracted and the feasibility of the method of second difference was verified. The experimental results showed that compared with the value of signal amplitude, the resolution of the depth of defects was higher while testing shallow defects if Pt was taken as the characteristic quantity of shallow defects and at the same time, the problem of the seriously decreasing resolution of the characteristic quantity of defects caused by the lift-off of the testing probe could be solved.