In order to improve the detection distance and section location accuracy of rail fracture with ultrasonic guided wave and ensure the safety of rail during service. In this study, Barker code encoding and Kaiser window function were used to modulate the excitation signal, expand the excitation signal time width, enhance the energy of the transmitted signal, and improve the resolution of the defect signal through pulse compression processing of the detected signal. The finite element simulation was carried out, the rail 3D simulation model was built, and the rail fracture damage was simulated. When the rail fracture degree is 20%, the peak-to-peak ratio of the main wave packet signal and the adjacent wave packet signal of the direct wave signal is 1.065 by using multi-period sine wave signal excitation, while the peak-to-peak ratio of the main wave packet signal and the adjacent wave packet signal is increased to 2.542 by using Barker13 coded signal excitation. The characteristics of defect echo signal under different fracture degrees are analyzed, and the amplitude of the echo signal intensity changes above 40 dB by Barker13 coded excitation signal. The finite element simulation shows that the encoded excitation and pulse compression technology can effectively improve the resolution and signal amplitude of the detected signal. Combined with the offline long-distance rail detection experiment, the detection signal obtained by using multi-period sine wave signal has complex components and difficult calculation of time difference. However, pulse compression technology can effectively improve the signal-to-noise ratio of detection signal and improve the signal resolution of the initial wave signal and the echo signal, and the accuracy rate of section positioning is 99.3%. Coding excitation and pulse compression technology can improve the amplitude of detection signal and the accuracy of detection and positioning effectively, and provide technical means for long-distance rail section positioning.