In this thesis, ACFM detection technology in nondestructive testing technology is used to design a probe that can detect track defects, and the advantages and disadvantages of traditional U-shaped probes and new C-type probes are compared to determine an optimal detection probe scheme for track detection. Using COMSOL Multiphysics software to simulate and calculate the nondestructive testing effect, and the distribution of the normal signal and tangential signal of the magnetic flux density above the defect is obtained, and whether the detection probe can play a good detection effect, and the feasibility of the detection probe scheme is determined after the detection of the rail surface defects, and the different parameters of each part of the detection probe are analyzed to obtain the optimal solution of the parameters of each part of the detection effect, so as to achieve the best detection effect.