Aiming at the pipeline stress detection and quantitative research, a pipeline stress detection method based on electromagnetic detection principle is proposed. Based on the J-A model and molecular current theory, a mechanical magnetic coupling model of the pipe is formulated. Combined with the magnetization curve of ferromagnetic materials under non-hysteresis condition, the influence of external magnetic field and stress on the magnetic field of the pipe wall in the magnetization direction is calculated by using the mathematical model, and a systematic experimental study is carried out. Results show that with the increase of the stress intensity, the electromagnetic stress detection signal of the pipeline increases firstly. Then, the magnetization direction decreases ( the direction of change is reversed). There is a linear relationship before and after the flip point. However, when the rate of magnetic signal changes, the magneto dynamic sensitivity changes with the increase of external magnetic field. When the magnetization curve is at magnetic saturation (magnetic field intensity is greater than 20 KA/ m), the stress has little effect on the magnetization of ferromagnetic materials. When the magnetic field intensity is about 5 000 A/ m, the stress has more significant effect on the magnetization.