Abstract: In this study, a quantitative detection method for aflatoxin B₁(AFB₁) based on TMR magnetic sensor and magnetic chromatography test paper was proposed to solve the problems of complex operation and longtime detection of AFB₁. In a vertical uniform magnetic field, the TMR magnetic sensor was used to detect the response signals of the superparamagnetic nanomagnetic beads on the test line (T line) and the quality control line (C line) of the magnetic chromatography test paper, and by analyzing the change of T/C value with AFB₁ concentration, a standard curve was drawn, and finally, the quantitative detection of AFB₁ could be realized. The results showed that the detection results of the magnetic bead response signals were basically consistent with the simulation results of the linear magnetic dipole model. The method showed good linearity when the concentration range of toxin was 0.01-10 ng/mL. The measurement time was 40 s, indicating that it could be used for instant on-site detection.