Aiming at the problem of different directions of erack defects on the surface of the pipeline, a crack detection method based onbalaneed electromagnetie technology is proposed. The eleetromagnetie distribution of the inmer surface of the pipeline under the time-harmonic electromagnetic field is analyzed by Maxwell's equations. According to the distortion of magnetie flux and induced current, thedeteetion mechanism and signal law of eracks in all directions on the pipeline surface are analyzed, and the effectiveness of the balancedeleetromagnetie technology for all angle detection of pipeline cracks is proved. The finite element method is used to caleulate and analyzethe electromagnetie distortion degree of the inner surface of the pipeline when the crack is at seven diferent angles to the detectiondirection, and the corresponding induced voltage signal is obtained through simulation, Aceording to the simulation result, the validitytest is carried out. Results show that the balaneed eleectromagnetie deteetion technology can realize the full angle detection of the surfaceerack of the pipeline. The deteetion signal feature is divided by the detection direction and the crack at an angle of 30°. The 0°~30°signal feature is the first trough followed by the peak. The amplitude of the detection signal gradually decreases as the angle increases,and the peak-to-valley spacing decrease rapidly, 30°~90° signal features a peak first and then a trough. The amplitude of the deteetionsignal gradually inereases as the angle inereases, and the peak-to-valley spacing slowly decreases; when the detection direction is 30°t0the crack, the indueed voltage signal has a double peak-valley feature, And the peak-to-peak value is the smallest. This method providesa theoretical basis and experimental hasis for the quantitative study of the erack angle on the pipe surface.