In order to accurately determine the location of the defects in pipeline and reduce the complexity of echo signal, an electromagnetic acoustic transducer structure with unidirectional propagation in the pipeline is proposed. According to the theory of electromagnetic acoustic transducer, the mathematical models of the magnetic field, displacement and ultrasonic superposition were established, and the finite element simulation analysis of wave fluctuation displacement of unidirectional electromagnetic acoustic transducer was carried out. In the experiment, the double coil excitation method was used to control the propagation intensity of T(0,1) mode guided wave. The results show that when the distance between adjacent wires of the transducer is λ/ 4 and the delay time is T/ 4, the amplitude of echo signal on the weakened side is almost zero. The amplitude of the echo signal on the enhanced side is significantly enhanced, and the relative sensitivity to the intensity of the acoustic wave generated by the traditional transducer is 5. 88 dB. The unidirectional T(0,1) mode electromagnetic acoustic transducer realizes the control of propagation intensity and direction, improves the signal-to-noise ratio of detection signal, provides theoretical basis for accurate identification of defect orientation, and provides accurate defect location information for pipeline detection engineering application.