The key to accurate quantification of magnetic flux leakage（ MFL） detection defects is to describe the geometric relationship between the defect and the magnetic flux leakage signal. The effects of four different shape defects（ rectangular

cylindrical

trapezoidal and asymmetrical triangles） on the magnetic flux leakage signal are studied. Finite element modeling of four different shape defects is carried out

and analyze on effect of different shape defect length

depth on the signal of leakage magnetic

and the contrast analyze on different shapes of defect magnetic flux leakage signals with regard to the same conditions

finite element simulation are verified through the experiment

the signal curve of the two with the same change trend. The results show that the distribution of the magnetic flux leakage signal is closely related to the shape of the defect. Result shows that in the same case

the amplitude of the magnetic leakage signal of the rectangular defect is the largest

the effective width of the waveform is the widest

and the signal intensity is the largest. The amplitude of the magnetic leakage signal of the cylindrical defect is the smallest and effective width of the waveform is the narrowest and signal strength is the lowest.